Bug: First Reports
This page is for first report of any bugs. Just add a quick description and a pointer back to the discussion thread in the forums. The purpose of this page is to consolidate bug reports so that they are easy to find in the early stages. Please continue to report individual account issues to support. (This page is just for community use, it is not monitored by SmartThings staff.)
- 1 Bugs from a Specific Platform/Hub Update
- 2 Mobile App Bugs
- 3 General Platform Bugs including Mode Changes Failing, Database Corruption, IDE problems and Mysterious Events (Also see the Smartapps Section and the Platform Updates Section)
- 4 SmartApp and Routine Bugs
- 5 Smart Home Monitor
- 6 SmartLighting
- 7 ADT/SmartThings Security System ( bugs specific to this model line)
- 8 By Device/Integration
- 9 Bugs reported by developers regarding the ST groovy implementation
Bugs from a Specific Platform/Hub Update
Hotfix September 20, 2016: multiple bugs 
platform update: major lag processing sensors 
platform update: various mode change issues 
Sept. 30: all scheduled tasks failing including mode changes 
Multiple new reports of schedules failing and routines timing out 
November 10 platform update broke the ability to change arm/disarm state in SHM for about half a day after the update completed. This was then repaired. 
November 10 platform update broke the ability for third-party apps to communicate with SmartThings, instead redirecting the page to the SmartThings IDE. This impacted smarttiles, google home, IFTTT, Harmony, and other services using OAUTH. This was repaired a few hours later . 
November 17 hub update failed for about 10% of the first set of customers, causing their zigbee devices to then be unreachable. ST halted the rollout of updates and is working on a fix for the affected customers. 
December 1 update caused some initial problems, listed on the official status page. Although these were supposed to be fixed by the afternoon, multiple community members continue to report problems, particularly with zigbee devices and not being able to add new zigbee devices. It's not clear why some members are affected while others are not. Make sure you report the problem to support if you do have the issue. [/ Community discussion] Update: Smartthings staff have now confirmed that some customers were affected by multiple zigbee issues after this update. These include Motion sensors continually sending false alerts. [Staff confirmation]. Continue to report the problems to support if you have them.
Hub firmware was updated to 17.11 in a rolling release that affected a few hundred customers at a time. One community member reported that their devices started failing and they got repeated "hub update" and "zwdebug" messages in the log. Support is investigating. [community discussion] on March 22, the rollout was halted because multiple customers reported that the update failed, leaving the hub with blinking red or magenta lights for hours and the system inoperable. [discussion thread]
Hub firmware was updated to 17.12 in a rolling release. Several community members reported that after the update completed, they lost control of zigbee devices, particularly Osram and Wemo lightbulbs. This appears to be because the hub was off-line for long enough that the bulbs reverted to the ZLL profile instead of the ZHA. Resetting the individual bulbs and then re-adding them to the smart things hub should solve the problem. [Staff discussion]
Some Community members report system delays since the new firmware was applied. [community discussion]
After a hub firmware update, some community members began having problems with Z wave devices where the manufacturer field would be set to all zeros and the device would no longer respond. This seem to particularly affect Yale locks, but other zwave devices were affected as well. In June 2017, SmartThings engineering staff said that a fix had been found and would be applied in a future update. Meanwhile, some community members have reported that they have been able to get the device to work if they just keep excluding it and re-adding it to the network until eventually they get valid entries. See the [community discussion].
Multiple problems reported with the hub V2 firmware update 18.18, particularly devices dropping offline or failing to update status. If you are having issues, report them to support.
Also, with the new update, community members reported that it was no longer possible to add A new Xiaomi device from the original line. These devices would work OK for about an hour, and then leave the network. Since the Xiaomi devices are not certified for the ZHA profile, they've never been guaranteed to work 100% with anything except their own Gateway, but they are very inexpensive, for some community members do use them.
Several different kinds of problems reported with the hub V2 firmware update 18. 20. Also there were some plan changes which were not announced ahead of time, including no longer having the stock device type handler report physical vs digital events. This last change means that some double tap smartapps no longer work. [official announcement thread]
After a hub update, many battery operated devices now show 100% all the time. If you have this problem, reporter to support. Community discussion
On November 16, a hub update was pushed out to all V2 hub owners. While the update seems to have generally gone well, some customers are reporting that the hub gets hung up during the update and never completes. If this happens, do not reboot the hub – – contact support. Other people report that the update completed, but after that some of their other devices were nonresponsive. If this happens, try taking the hub completely off power (including removing any batteries) for 15 minutes, then put it back on power, then reboot it using the option in the IDE. This will resync the network for many accounts. official announcement and community discussion
On December 4, a hub firmware update was pushed out for the US V2 and the UK hub. It seemed to go OK for most people. Some people reported one or two devices would not come back online afterwards. And a few people reported that their hub went off-line all together and would not come back. If you are having any problems, please contact support. Community discussion
An emergency update on January 12 to fix a video problem then caused z wave issues for some users. Running multiple Z wave repairs in sequence appeared to fix the issues for some users. Report it to support if you are having problems. Community discussion
Mobile App Bugs
All 3 mobile apps were updated: multiple bugs including not being able to find smart apps, frequent log outs, modes not working, widgets not working, routines not working, not being able to view video in smart home monitor 
Can't find list of smartapps 
Can't log in. Confirmed by ST staff as a backend problem affecting all OSs. 
Windows app frequently logs out 
Problems with mobile presence detection, particularly in the UK, but also some reports from the US 
Android app update 2.2.2 results in an error when trying to save a new Automation from multiple smartapps, including SmartLighting, Core, and Lock Manager. (The IOS version does not have the same bug.). The bug was fixed later in the day. 
A mode change will occur as scheduled, but the mobile app will continue to show the previous mode until there is a hard refresh. [Community discussion]
February 11: [mobile app just spins, can't log in]. This appears to only be affecting some customers. Staff has reported that the error was caused by the contact book timing out for some customers, and a fix has been applied.
Colors changed on some of the icons on the things screen, so that some are blue and some are green. It turns out this is part of a change for some device type handlers, and for whatever reason it is being rolled out a little at a time. [community discussion with confirmation from support]
Some icons no longer respond to presses in the android app. This is a confirmed bug. There is a workaround if you are willing to change some code in the DTH. Definitely report this to support if you are affected. [Community discussion detailing the workaround].
-IOS Mobile App Update 2.3.5: multiple users reporting that smartapps will not load. Community discussion. SmartThings staff have now reported that the problem has been identified and will be fixed in a future update.
-Android Mobile App Update 2.3.5 and 2.3.6: multiple users reporting crashes and that the app is running their phone's battery down very quickly. community discussion Staff have posted that a 2.3.7 release is expected shortly to correct the battery drain problem, but it may not correct all of the other problems that have been reported so far.
- some members reporting that after the recent app update, mobile presence no longer works the same way with multiple locations. Community discussion Reportedly fixed with update 2.3.6
- some U.K. members reporting problems with the Android app. community discussion
- multiple people reporting that they are unable to save favorites in the new version of the app. If you have this problem, contact support. [Community discussion]
- SmartThings engineering staff is asking for help in investigating an issue were some people are reporting that they are frequently getting logged out of the iOS mobile app. If you are having this problem please report it in the format requested in the [community thread]
- A mobile app update completely broke VoiceOver usage, making the app unnavigable for those dependent on switch navigation or voiceover. SmartThings is aware of the problem and has promised a fix in a future update. [Community discussion including staff comments]
- IOS 2.7 app update: some community members, but not all, are reporting that the widget display for this app update is taking up too much space and blocking out other notifications. If you have this problem, report it to support. Community discussion
- Geopresence for the SmartThings mobile app appears broken in iOS 11, although community members report that geopresence is working in other apps like life 360. So it looks like there may be a change that SmartThings needs to make in order to remain compatible. Community discussion. Update: Smartthings has it knowledged the issue and will be redoing the way they handle presence. A new beta was opened in November to test the changes. official announcement of beta test
- Some community members reporting that if they have both a Samsung account and a SmartThings account with the same email address, both the IDE and the app things listing is blank. Unfortunately, there is no simple workaround for this. If you have this problem, contact support. Community discussion
- January 4 some community members are reporting that they can't log into the app and they are being forced to create a Samsung account (rather than a SmartThings account), but then that doesn't work either. Support has acknowledged the problem but doesn't have a current fix. If you were affected by this, contact support. Community discussion
-January 15 some community members reporting that they cannot add a new routine in the mobile app Community discussion
-January 17: Manual device control through the smartthings mobile app is failing for some users. Community discussion
General Platform Bugs including Mode Changes Failing, Database Corruption, IDE problems and Mysterious Events (Also see the Smartapps Section and the Platform Updates Section)
because of the hub and platform updates this month, problems were reported as related to the update. See the platform update section for this month.
Garage door opening and closing randomly 
IDE errors and severe lag ( according to ST staff this is related to the other lag and time out issues, it's not just the IDE) 
Mode changed mysteriously to morning in the middle of the night 
GITHUB format changed, can't find code 
Lights turning on when they were not scheduled to at the same time several days in a row 
Mobile app asked for authentication code, then appears to have completely reset. (Staff suggests it may just have created a new location.) 
Daylight savings time fail 
Multiple problems reported related to the November 10 platform update. See that section above.
November 12: multiple people writing that device reports, particularly from sensors, aren't being processed. Many automation failures even though the devices show as active.. 
November 24: Device control and scheduling failures affecting customers on the NA01 shard. Smartthings engineering is aware of it and is working on a fix. Some customers still reporting problems on Friday morning. 
December 10: Major cloud outage [official status page]
December 22: Multiple community members, but not all, reporting that routines scheduled to run at sunset never fire. The current workaround is to change the rule to run at a specific time. [community discussion]
December 27: multiple strange problems with people either unable to login or having missing devices or even a missing hub from their account. Support is aware of the problem and there have been on and off notices on the status page. [community discussion]
February 2: [system outage]
February 28: Amazon Web Services outage is affecting cloud services all over the world, including a number of SmartThings services, as well as some IFTTT and harmony services. [Community discussion]. Amazon says they have identified the problem and have a fix, with some websites beginning to come back around 6 PM Eastern. [USA Today on the outage]. SmartThings returned for most community members around 7 PM Eastern.
Mysterious network pings causing random events, including [garage door opening unexpectedly]. [another garage door] It's unknown if these events were related to the recent hub update or not. Report it to support if it happens to you.
March 11: random instability, bad enough to be reported on the official status page. The status page says the problem was resolved after a few hours, but some community members are reporting that they are still having problems with sensors [community discussion]
March 27: multiple members report everything has gone dead. After an hour or so, it came back intermittently. This was reported as resolved in a few hours. [community discussion]
-Some members reporting random events, lights turning on unexpectedly, Core routines not running, etc [community discussion]
-April 13 Major outage: Loss of cloud operations with random results: some devices not working, some turning on unexpectedly, some automations delayed for 10 minutes or more. Outages appeared random and intermittent, making it difficult to troubleshoot, but the issues appear to be on the cloud side. [official status page] [community discussion] The company reported that the outage was resolved early afternoon on the 14th, but some customers continue to have issues.
-( this issue may have begun in March, it's not clear) multiple members reporting multiple devices show as "off-line" and then have unpredictable results. Some can still be controlled with echo but not from the app. Some failed to function in routines and other automations. Just a lot of variation. Both Z wave and zigbee devices have been reported as affected. At this point support has acknowledged a known problem, but no workaround as yet. Some members report that if they turn health check off through the IDE and then turn it back on the devices will be OK again for a little while. It does seem to have some relation to the new healthcheck feature but, again, no work around yet. [community discussion]
-On April 20, A platform change was made which introduced a bug into the way that some device responses were handled. This affected many different device type handlers. In some cases, such as thermostats, certain features stopped working like the ability to change mode. In other cases, devices were marked as off-line which were not. The problem was identified by community developers and smart thing staff were able to apply a fix on April 25, although some member say they are still having problems. This appears to be different then the problem which was reported earlier in the month of devices just being marked off line. [community discussion in the developer section of the forum]
-Ongoing intermittent delays where commands can take several minutes to execute. This problem was first reported by some members in April, but by May there were multiple reports involving both zigbee and zwave devices. The problem comes and goes, and sometimes affects different devices, making it difficult to diagnose. Rebooting the hub appears to fix the problem for a few hours, but then it will return. Support has not yet acknowledged the issue, but is treating each individual report as a local interference problem. If you are affected, definitely put in a support ticket. [Community discussion]
-May8: some members reporting that they are getting error messages when using the IDE. Community discussion
-May 10: weird new login screen for the IDE. This one isn't a bug, it's just an unannounced change. Since some people now have Samsung IDs. rather than just SmartThings IDs, The new login screen sorts that all out. Staff have posted an explanation in the Community discussion thread.
-About a dozen different community members are reporting strange new reliability issues in June, particularly extensive delays between a trigger event and a routine or automation firing. Also problems with device is becoming unavailable and strange zwave messages. These were all things that were working fine in May where multiple problems appear at once. It's not clear whether any of these reports are related to each other. It's always possible could be individual hub failures and it's just that as the number of customers increases there are occasional individual failures. No staff comment yet. Anyone having these problems should begin by reporting it to support. It may also be helpful to turn off device health, but that doesn't help everyone. [Community discussion]
- June 17, System outage affecting some customers. Acknowledged on the official status page. [community discussion]
- Multiple forum members reporting that devices which used to be just fine are now reporting "off-line" frequently. [Community discussion]
- 23 August platform outage including the IDE and the mobile app. [see the official status page.]
- 30 August platform outage including the IDE and the mobile app. [see the official status page.]
Multiple community members reporting that automations that used to run fine are now significantly delayed, even up to several hours. If you have this issue, report it to support. [Community discussion]
October 4, 2017. Platform outage lasting less than 1 hour. See the official status page.
October 5, 2017. Platform outage affecting some customers, but not all, lasting several hours. See the official status page. The problem has been reported as a result, so if you are still having issues, contact support.
October 14, 2017. Routines and automations running hours ahead of schedule. If you have this problem, report it to support. See the official status page for updates. community discussion
Some members, but not all, reporting that routines that used to work just fine are suddenly randomly failing to recognize the appropriate mode and consequently are running at the wrong times. This includes both regular routines and some smart apps like "notify me when." If you have this problem, definitely report it to support, as they are still collecting information on it. Community discussion ( this was eventually confirmed as a known problem for the UK region)
Zwave repair taking a long time to run, or never completing. Support says it is a "known issue." Just started around the beginning of December. If you were having the problem, report it to support. Community discussion
January 3-4. Platform outage affecting many users, but not all. Device commands delayed or lost and the mobile app not working. Some users experienced an outage of five or six hours, others longer. The official status page list of the problems as resolved on the second day, but then a new group of users reported similar problems. If you are having these problems, definitely report them to support. Reported on the official status page Community discussion
Jan 16. Platform outage affecting many users, not sure how many. Listed on the official status page. Community discussion
SmartApp and Routine Bugs
Time-based routines failing 
Mode changes but then nothing triggered by the mode change runs 
Voice notifications sometimes missed or only plays partial, multiple smartapps 
Core Pistons executing randomly 
Scheduled apps failing 
SHM screen stuck on "loading" for hours, cannot arm or disarm smart home monitor. Affecting both iOS and Android. 
Multiple people reporting either security error messages or timeout messages when using either the IDE or the mobile app. Engineering staff have confirmed that this is an issue with one of the databases. It is not related to any specific smartapp, including core. It is only affecting some customers. [staff discussion]
SmartThings made a platform change for security reasons which broke several smartapps that display camera images. Note that this is different from The problems with blink cameras that occurred about the same time. [Community discussion]
Multiple people reporting that some Core Pistons are failing, but routines are working. [community discussion]. In Some cases, the problem appears to fix itself after an hour or so.
-something changed in the way that smart things allows for third-party authorization, and consequently some third-party apps are no longer able to connect with SmartThings. This includes smartrules and beaconthings. The developers are working with smartthings to try to find a solution. community discussion
November 5, 2017. The daylight savings time change appears to have broken webcore operations for all time based pistons . [Community discussion]
January 1: some custom smartapps failing. The problem is "known" but the reason is not. Reported on the official status page
January 2: time-based rules failing for some users because one of the timezone information providers is down. official status page
Smart Home Monitor
Video clips only playing if downloaded 
Video clips not playing 
SHM screen stuck on "loading" for hours, cannot arm or disarm smart home monitor. Affecting both iOS and Android. 
Speech notifications not working with some SHM alerts. After investigation by SmartThings staff, two separate bugs were identified, and a fix has been promised soon. [community discussion]
Smart home monitor not loading. Reported on [the official status page].
April 7: Some members report that if a sensor is included in armed/away but not in armed/Home and they have the paid scout monitoring that if the sensor detects motion in armed/home, Scout will consider it an intrusion alert even though SmartThings doesn't. Support is looking into it. There is a workaround using core and a virtual motion sensor, but that will not work if the Internet is out. [Community discussion]
Smart Home Monitor problems, including being unable to dismissed. This is been reported on the official status page. It was reported as resolved a few hours later.
SmartLighting has changed and now if you try to create a new automation there is no way to specify the button number that you want to use on a minimote with the stock device Handler. Any other device type handler which does not specify the number of buttons field will have the same problem. . Update: this was fixed in the minimote device type handler on 6 December 2016.
Multiple people reporting that local SmartLighting automations are failing, but routines and. Cloud-based versions of the same SmartLighting automations are working. [community discussion]
-May 16: Multiple problems being reported. This may be related to the smart home monitor problem which has been reported on the official status page. It was reported as resolved a few hours later.
ADT/SmartThings Security System ( bugs specific to this model line)
Right now there is only one Community discussion thread in the forum for this model line, so the links in this section are to specific posts. Hopefully the form will eventually be re-organized with a separate section for this set of devices.
The system went into programming mode on its own and consequently disarmed itself. Community discussion
Mobile app displays error message when retrieving armed status Community discussion
severe lag for Hue bridge 
Hue bridge has a bad address or some bulbs unreachable from ST ( but work OK from other apps) 
Hue bulbs marked as "unreachable" still work through the Hue app but don't work through SmartThings 
Samsung SmartThings motion sensor false positives 
Samsung Smartthings multisensor false positives 
LIFX wonky 
Samsung powerbot vacuum not working 
Arlo clips not displaying 
GE/Jasco in wall switch indicator lights suddenly change behavior 
Multiple Hue problems, including severe lag
Friends of Hue (bloom, strip) and the old Hue Lux that used to work with smart apps now don't seem to respond to smart things, although they continue to work from the native hue app 
SmartThings sensors keep dropping off network, or only report temperature, or battery reporting incorrect  (includes ST staff comments)
Sonos plays once or twice, then stops, or fails altogether 
Sonos stutters 
November 12: multiple people writing that device reports, particularly from sensors, aren't being processed. Many automation failures even though the devices show as active. 
Hue bulbs showing significant delay between bulbs when a group request is processed through SmartThings, creating a popcorn effect. Reported as new in the last few weeks. 
Samsung smart vacuum won't connect to SmartThings even though it works fine with the Samsung smarthome app. 
Two people reporting that they would create a simulated switch on one day, everything would work fine, and the next day the simulated switch would have disappeared from their account. 
Smartthings did a zigbee firmware update in early December to allow over the year (OTA) updates of the SmartThings branded devices. Since then, multiple community members have reported that when the OTA check occurs every day, their Osram RGBW devices do strange things, generally reverting to white and coming on full brightness. Other community members are not having a problem with these devices, so it may depend on the firmware level of the Osram device. If it happens, report it to support. [Community discussion]
The same zigbee update is causing some zigbee motion sensors to think they are supposed to be updating when they are not, and issue multiple false motion alerts, sometimes over many hours. So far this has affected both the Samsung brand motion sensors and the hue motion sensors which are connected directly to the smartthings hub. [community discussion]
Around December 15, multiple community members begin reporting that they were having odd device communication failures, and that those failures could affect devices of any protocol. The devices appear to be reporting in OK, but instructions to the devices were sometimes logged but not performed. Both Z wave and zigbee devices could be affected. Rebooting the hub might cause things to be OK for a few hours or a day or so, but then the problem would return. Support is currently collecting all reports of this issue. It is definitely not affecting all customers, but it is affecting some, and both V1 and V2 hubs have been affected. [Community discussion, including the support ticket number you should reference when reporting this problem]
Some members report GE switches randomly changing parameters, particularly for when the indicator LED comes on. This might represent back end changes. [community discussion]
V2 Hub batteries Many community report leaking batteries in V2 hubs. After investigation, SmartThings determined a firmware update was needed and this was distributed on 30 January 2017. [Community discussion]
Blink Cameras found that some server outages on their side were being caused by excessive polling from outside services, including SmartThings, and they decided to cut off this integration option. After discussion with RBoy , who makes a paid smartapp that was developed in consultation with Blink, they decided to allow one version of his smartapp to continue to have access temporarily while they try to find a long-term solution. The other smartapps will not work. [community discussion]
Alexa As of January 30, a few community members have reported that Echo commands that previously worked are no longer working. In most cases, this was a situation where the person had more than one SmartThings location, and somehow Echo appeared to have switched to a different one. Details are not clear yet. [community discussion]
Color bulbs are coming on at a different color than they used to, particularly shades of white. Smartthings staff explained that in order to try to synchronize different brands of bulbs, such as LIFX and Osram, they have changed the way color temperature is set. So new defaults are now being used. If a customer had previously individually customized color temperature on a bulb in order to attempt their own synchronization, they might now be seeing unusual results. [Staff explanation of the new defaults]
Alexa Several community members have reported that in the last week or so they are starting to see multiple log entries for Alexa but the devices don't change state, it's just some kind of polling or something. No official response yet. [community discussion]
IFTTT authorization fails. This problem appears to have been corrected on March 1. If you're still having problems, contact support. [community discussion]
Google Home processing a first home automation request, but then replying "something went wrong" for any further requests. Google support has confirmed that it is a problem on their side and they are looking into it. [community discussion]
GE Switches using the Stock DTH' suddenly reverse the behavior of the LED indicator, so that it is off where it used to be on. This is probably the same issue that occurred in January, where a backend change was made that introduced this error. If you are affected, report it to support. [community discussion]
LAN Devices like Hue and Sonos suddenly showing up on the things list when they weren't there before. This is a change having to do with the rollout of LAN Connect. There is now an automatic discovery of any devices on the same local network as the hub and the devices are added automatically, you cannot opt out of it. You can go back in and remove them individually, but they will be re-added every time you run a "add a new device" for any device of any protocol. Official position is that this is a new feature, not a bug. [Community discussion]
WiFi Devices like WeMo and Ihome frequently using losing contact or failing to update status. Multiple people reporting this in the forums in early March. It's not clear whether this is related to the LAN Connect change, to the new wellness check, to the new versions of the mobile app, or something else altogether, but it is affecting multiple people. If you are affected, report it to support. [community discussion on WeMo]
All zigbee Devices lost connection could be just a coincidence, but two different community members reported that all of their zigbee devices dropped off line about the same time. If you have this problem definitely report it to support. [community discussion]
Zwave Plus Devices not updating status. This is been reported for both the new GE switches and the new Leviton switches. [community discussion]
UK SmartThings socket overheats. This applies only to the UK version of this device. Several community members reporting that plugs don't quite fit in the socket and this can lead to a fusing problem. [Community discussion]
First Alert Z Combo Smoke Alarm After the April hub firmware update, multiple community members have reported some false alarms from these devices, in some cases more than a day after the update completed. If you have this problem, contact support. [community discussion]
Google Home integration not working. [community discussion]
Horstman Z-Wave Thermostat reported by multiple members as previously working and suddenly showing strange behavior around April 19. The device except the set command but then nothing ever happens. [community discussion]
Honeywell Thermostat reported by multiple members as previously working and suddenly showing strange behavior around April 19. This may be the same problem that is affecting the Horstman Thermostat. [community discussion]. If you are affected by any of these problems, contact support.
Multi endpoint zwave Devices no longer working again, the devices were previously working well. [community discussion]
IFTTT Maker Option IFTTT introduced a new maker option for people who want to create applets for others to use. Multiple reports from the community that the IFTTT site would not allow a SmartThings device to be added to an applet through this option. One community member reports it does work if you Are using the IFTTT mobile app instead. [community discussion]
Lutron Caseta Devices The initial integration works fine. However, after that, if you try to add one more Lutron device it just won't add. If you have this problem, report it to support. [Community discussion]
ISP5 Plugs that previously worked fine now go off-line to smartthings multiple times a day, but still work fine with HomeKit or their own app . [community discussion]
Arlo Cameras interfering with routines. Community members report that support says this is a known problem. [Community discussion] July 1: Smartthings staff say that cause has been found and a fix should be deployed soon. 
Xioami Devices are very inexpensive home automation devices from China, but they are not certified for the ZHA Profile and have always been somewhat idiosyncratic. Beginning with the hub v two firmware update 18.18 in late July, xaomi devices which were already on the network continued to operate OK, but any new device from the classic line that was added would remain on the network for about an hour and then drop off. This isn't really a SmartThings problem because the devices are not certified, but it is obviously frustrating for people who have invested in these devices and had them previously working OK. The newer Aqara line from Xiaomi doesn't seem to have the same problem, but again, can't be guaranteed to work in the future as it is not certified either. [community discussion]
Zwave Switches using the stock handler The firmware update in early August re-created an earlier problem where some switches, particularly the GE 12 722, would switch orientation so that the top was off and the bottom was on instead of the other way around. This is a parameter error which can be fixed by using the community-created Z wave tweaker, but it is an error in the official DTH. Discussion of the fix in the [forum thread]. If you have this problem, report it to support because if they don't fix it on their side it may return with the next firmware. Note that an additional change to the same DTH means that [the "physical" attribute of an event is no longer filled in], which will break some doubletap apps and other smartapps which depend on knowing the device was manually activated.
Google Home not recognizing new devices. This only affects some customers. Both google support and smartthings support are aware of the problem and engineers are working on it. For at least some customers, the problem appears to be related to device type handlers for thermostats which list the device as both a thermostat and a switch. staff comments
Lutron SmartBridge not found by official ST integration even though it works fine with other integrations like echo or harmony. Some members are reporting this problem, but not all. If you do have this problem, contact support. Community discussion
SmartThings IFTTT Service failed on September 6 for a significant number of users. This was first reported by UK users, but that may just of been because they were up first. This included applets that had been running fine for many months. This was fixed after a few hours. If you still have this problem, report it to support. Community discussion
SmartThings/Life360 Integration failed some users, but not all, report that the life 360 integration stopped working with SmartThings on September 2. The life 360 app itself was working, but location updates were not showing up in SmartThings. If you're having this issue, please contact support. community discussion
SmartThings/IHome integration failed. Support is aware of the problem and was reported as fixed on September 12. If you are still having the problem, definitely report it to support. community discussion
Google Home Linking/Unlinking problems Support from both companies is aware of the problem, but it seems pretty complicated. See Community discussion including staff comments
Arlo Cameras community members first begin reporting slowdown problems with Arlo cameras in June, but the issue has now been added to the official status page and new problems appear to have developed. In depth community discussion
Nvidia Shield Link keeps disconnecting. Apparently this is a known error affecting some accounts. Community discussion
Echo two separate problems. First, echo will respond to a request by saying it was unable do it, even though it was. Second, harmony activities are now imported as scenes and this is causing multiple issues. Such as not being able to turn one off. Report both of these to both smartthings support and Amazon support. Community discussion
Samsung televisions. A firmware update to the smart televisions broke the SmartThings integration. Support is aware of the problem and is working on it, but it has now been six weeks and still no fix. If you have the problem, contact support if you have not already. community discussion]
Minimote multiple people reporting that this device stopped working around the first of the year even though it had previously been working fine. If you have this problem, report it to support. Community discussion
Bugs reported by developers regarding the ST groovy implementation
"Ghost" routines (null label) 
HubAction calls crashing hub [community discussion]
GitHub integration seems to have reset, all links missing. If you have this problem, contact support, as they are investigating. [community discussion]
-Existing device type handlers showing a change in behavior, including configure no longer working. [community discussion]
-Reported beginning April 20. Response() not being processed correctly, Breaking existing device type handlers and some smart apps. Staff investigated and found a bug. A hot fix was applied on April 25, but some community members report still having problems. [community discussion]
-Android 2.3.5 update breaks sorting. Not strictly a groovy issue, but it is affecting developers. Sort levels are being forced on the UI, and ignoring the Enum value set by the developer. So days of the week are being displayed in alphabetical order. Numbers are being grouped so that the display is "1 hour, 1 minute, 2 hours, 2 minutes" rather than the developer's intended sort of "1 minute, 2 minutes, 1 hour, 2 hours." Etc. discussion in the announcement thread of the new release Fixed after a few hours.
-Device Type Handlers no longer tagging "physical" events in the physical/digital field. Turns out this is not actually a bug, it is a platform decision to no longer provide the physical tag as only some switches will report it and it fails if the event comes through a repeater. [Staff discussion of the change]