Well, I discovered that I can get all sorts of music playing within multiple apps at once. I had Pandora playing and then I clicked the headset button and got the music player going along with Pandora and dropped a call. I would consider that some serious software rule conflicts.
Meanwhile, Pandora did not mute/ pause on my outbound call.

Meanwhile, Pandora did not mute/ pause on my outbound call.
still a bug