Performance: Presence is not detected correctly
Description of the Issue
Presence detection, whether using a mobile phone or the SmartThings arrival sensor as the indicator device, is unreliable. The person might be shown as being away when they are home, or home when they are away, but not predictably.
Regions affected: all
Phone OS affected: all
Variable or Always Occurs: variable
The presence indicator should show as "present" when within range of the hub/home Wi-Fi, and "away" otherwise.
SmartThings official response
They are aware of the issue and considerate generally due to local interference or other networking issues. They offer several support articles for methods of troubleshooting.
Official support articles on troubleshooting presence sensing 
May or may not be related to a UK bug where a presence sensor always shows as present. Bug:_presence_sensor_always_home_(UK)
The three main methods of indicating presence to SmartThings are a mobile phone, the SmartThings arrival sensor Zigbee device, or the third-party service life 360. Many people find that if one of these three methods does not work, one of the other two may work better. But which one works best for each person will vary.
Official support article on Life360 
If the problem is that the presence indicator shows a pattern of leaving and arriving many times when it did not actually physically leave, some people use a two device system that will ignore most of the "teleportation." This is discussed in the community.
Community discussions may be found in the following threads:
- Community created FAQ on troubleshooting mobile phone presence 
- Community discussion topic on the zigbee arrival sensor 
- Community project using a second device to eliminate " teleportation" errors 
- SmartThings staff conduct a poll in the community on presence issues with mobile phones []