My dude! I can’t believe this is such a pervasive problem! Pretty much every person that I know who connects their car to their phone runs into this issue especially in the case of couples where both phones are paired and it’s just some kind of headbutting match to see which device randomly wins out, which is guaranteed to be the phone you didn’t want connected. In theory their priority system, but in practice Bluetooth device discovery and the connection process seems rather random.

I wish my car had an option to disable auto connection and a prominently displayed button to explicitly connect to a recent phone upon request.