I had actually meant the first thing you responded to: being unable to play audio from the Bluetooth input while running the empeg screen controller app in Android Auto or in Apple Car Play.

But it’s possible that I’m remembering wrongly how it works. I abandoned Apple Car Play fairly quickly because it had a certain concurrency issue (can’t run Waze on my phone while controlling iTunes music on the car screen, I have to choose one or the other). I’m now no longer sure whether my car ALSO prevents concurrent audio from a different input source.