Hi I have problems with these sensors . I have two and are new. I tried to reset these ones several times with the hub 5 minutes everything works fine and in one moment the devices are away and is not true I’m in my house and the rooms are very close to the hub.
When you say very close to the hub. Too close can cause issues. Needs to be about a meter away at the closest i.e. Not on top of the hub.
And secondly I suggest you change the presence timeout setting in the IDE under Hub Utilities to 4 minutes from the standard 2. I’ve not had issues with these presence sensors since