Bluetooth Audio Streaming issues..

After updating my IPhone 6 to the latest OS, I've had an issue in my car (2015 Chevy Volt) with the bluetooth audio streaming. Basically while listening to the radio or XM or regular Ipod, I'll get a phone call. The call usually goes without a hitch, but as soon as I hang up, the audio streaming takes over totally ignoring the fact I was listening to the radio or XM before the call. I never had this problem before the OS upgrade so I don't think it has anything to do with my car. Has anyone experienced this before and if so, were you able to resolve it? It would be nice if there was an option in the IPhone to disable the audio streaming part of the bluetooth connection while still being able to make hands free calls.