Yesterday I received a few calls from my mother while at work, I was connected to a shared Bluetooth speaker disconnected from it by turning Bluetooth off and I took the calls came back inside and a few minutes later, a coworker had connected to the speaker their iPhone then called my mother who isn’t in their contacts list at all. I have an IPhone SE with the new iOS 17, they have an IPhone 14 Pro with the new iOS 17 we aren’t linked in any way. Why would their phone be calling numbers from my contacts?
Depends on what the BT speaker syncs.
The basic BT in my car syncs numbers called so changing the phone will still let you redial the last number that was called through the BT