I've tried most of the basic actions such as clearing cache, and killing tasks.
I just removed 'tune in radio' which is one of those apps that auto launch when blue tooth is turned on.
I noticed it gets really bad if someone else in the car has their blue tooth on, or if I am near another vehicle I suspect as having blue tooth.
I wish I could nail it down.
I have wondered if replacing a HU would help, but reading thru the audio forums, I am not seeing a lot of feedback related to using bluetooth from an android device to a new HU.