May be someone has seen this as I haven’t in over 3 years of using cell presence.
My phone, over the last 2 days, has been arriving and leaving the house even though I have driven 250 km away and flown to a different town.
In the past my phone would just leave and stay away but it’s like there is a tunnel back to my home. I have tried to see if it correlates with coming and going from cell or Wifi areas but it makes no sense.
You can see by the screenshot I left at 6:50 yesterday and have been out of town for 2 days but I still seem to be geolocating at my house for, what looks like, regular local travel.
At the moment my cell says I’m comfortably at home but I’m really 450 km away in a remote town on the coast of Vancouver Island, BC. I do have cell here but how this is getting screwed up is a mystery.
I’m starting to think maybe i shouldn’t reject having a chip implanted in me that ST can use to know my presence 
I keep reading of peoples troubles with accurate presence. For it to really work it has to be something that we always have, and for most of us that is a cell phone.
Check out this post on the AGPS WiFi section. You could be connecting to a WiFi device who’s MAC address is registered close to your house (long shot but you can verify if it if know the WiFI MAC address).
This was a strange one but it seems my sons cell phone was causing my cell phone presence to duplicate his activities as well as mine; that’s an ST bug that will never be found.
I have deleted my cell and re-added it. So far so good.
Did you log into the same ST account on both phones? If so then it would explain that. Ideally each phone should have their own account.
He has his own account but it is possible he goofed up. Hasn’t happened in a while now.