I currently have a QE55Q90RATXXC which I have connected to an Xbox One. I had to disconnect it earlier and upon reconnection, have found that the sound isn't working. I checked terrestrial TV, no issues there. I swapped cable, same issue. Interestingly upon disconnecting and reconnecting during the HDMI test, the sound started working, however once the test completes, the TV does the "autodetecting" and adds Xbox to sources /universal remote and the sound stops working again, even after unplugging the TV from the power etc. It seems that this is the part causing problems and can reproduce it each time, but I can't seem to disable this functionality, even after going in and turning off HDMI-CEC.