[Xperia XA2] No more phone connection over bluetooth since 3.3.0.16

I have problems too with my XperiaX since the last update to 3.3.0.16. When i activate BT the Connevtion is established but dies again after a short time. In the past there were mostly no problems with that (car is Volvo c30). Once i also had to unpair and conecct new, but i didn't try that not yet with 3.3.0.16.

@erikderzweite why make an answer instead of an update of above thread? make some confusion. Best is gather all in same place.

I also have problem to reconnect to my car (C4 grand picasso), before 3.3.0.16 everything was OK. Rebooting phone or unpairing and pairing sometimes helps but not always - next time the automatic connection does not work.
This is my first comment in this forum, I am wondering why the above answer is marked as correct, although provides no real solution. Is there real solution? How to debug?

I have disconnected and reconnected the phone to the car. But it only worked after some back and forth and not straight away (alternate start of the procedure sometimes from the phone and sometimes from the car). The connection is still lost after some time. Once it was restored when I woke up the display. But I couldn't reproduce that. It's just stupid when you start driving and then the connection seems to be disconnected.