I don't know if it could help you guys to solve the problem, but when I select Airplay at the audio output device in the audio output settings, both channels works with mp3 playback.
But of course when trying to play other format (DTS track, by example) with this setting, it does a bad noise (similar to the noise the TV does when there is only snow at the screen, don't know if it is clear...)
Maybe it can give you a hint about what is causing the problem.
But of course when trying to play other format (DTS track, by example) with this setting, it does a bad noise (similar to the noise the TV does when there is only snow at the screen, don't know if it is clear...)
Maybe it can give you a hint about what is causing the problem.