iOS background music quality degraded while in voice chat (Audio Session Options?)

Steps to repro:

  1. Open music app, play music w/bluetooth headphones
  2. Open unity app w/photon voice
  3. Join photon voice room
  4. Quality of music playing in background degrades significantly

I assume this is related to the iOS Audio Session options, but I've yet to find a combination of options that doesn't cause this issue. I've tried all of Photon's built-in presets (game, voip) and a variety of custom combinations. This is what I'm using atm:

new AudioSessionParameters()
    Category = AudioSessionCategory.PlayAndRecord,
    Mode = AudioSessionMode.Default,

    CategoryOptions = new AudioSessionCategoryOption[] 

Any ideas?