Try to make it simple I installed my phone and it came up James’s iPhone. Don’t know were it got that name but correct description. And everything worked as it was suppose to. So I installed Smartthings on my wife’s phone using my account everything was fine until I tried to add her phone. It would come up and say this phone has already been setup. But I only had the one phone setup. I deleted my phone and tried adding her phone and it would setup as my James iPhone, not hers, and of course I would get the same error when I tried to connect my phone. I think I got it to work but I don’t know if it is right. I would add my phone and put it in a room. I was then able to add her phone but it still came up as James iphone but I was able to rename it and put it into a different room. I took her phone out and it did show she had left and came back when I did. But I wouldn’t think that is the way it is suppose to work. Thank
Don’t login with the same credentials on two phones and try to use both as presence sensors.
Your wife needs her own ST login that you can then link to your hub. Then add her phone as a mobile presence device.