I have a new Verizon Kazuna etalk flip phone. It runs a version of AOSP. I've had problems getting the hands free functions to work properly. If I press the voice button and say redial, it tells me that the contact list is loading, and I can't make the call. Other times when hitting the call button on the steering wheel to dial the last number on the recent calls display, it says on the screen that the I'm out of the service area. Another issue is that the signal strength icon shows no service most times. I have service and can make calls by using the phone keys. I can hang up a call with the steering wheel button no problem. The phone and car have the latest software updates. My old flip phone worked fine with the car. I have a 2017 Prime plus with the 7" display. My iPhone works just fine with the car.
I did some research and found that the problem is a buggy version of Android 8.1, as others with different phones and cars have the same problem. Unfortunately, there is no resolution to the problem that I've found, anyway.
I sometimes have an unstable bluetooth connection and I believe that it's a bug. It's just frustrating because sometimes the connection is good then it's not.