iphone 12 mini bluetooth / car issues - only works if you prompt Siri 1st

I've had an issue with my new iphone 12 mini saying it's paired (with two different cars so it's not a car specific problem) with the car's bluetooth but then not actually broadcasting via the car speakers unless I prompt Siri to connect and then it seems to be fine. Just throwing it out there in case any one else is having an issue with the 12 - siri seems to fix the bug but nothing else does. Had an iphone 8 pair just fine with both cars before upgrading my phone so seems to be an iphone 12 bug for sure.