Settings > Bluetooth > Profiles/Options on a paired device (little graphic showing three volume sliders to the right of the paired device name)
If I disable Media Audio on the earpiece (Jawbone), this setting is forgotten every time the earpiece is turned off/on.
Does yours do the same thing? My old DroidX2 always remembered these settings. Very annoying, especially if also you have a car with in-stereo bluetooth phone/media and you want these settings fixed.