What kind of phone do you have? I have an android, pixel, in my bluetooth settings for paired devices I can change what I want to let use bluetooth and what I do not. For example I can say music only, enable/disable BT for hands free voice, enable/disable contact sync, etc. I would suspect it to be on your phone end not the head unit. Unless that does not happen in other vehicles. If you're android there are also some BT settings in the developer menu to tweak things more.2014 Sportwagen. Every time I get any type message on phone while in car and the phone has BT automatically connected it switches from radio to BT Audio. SMS, FB messenger, SnapChat all do it. Anyone had this issue and solved it?