For the last maybe few weeks I have had issues with the 7.1 surround sound configuration on my xbox one x and plex. Normally I have my xbox configured for PCM audio with the 7.1 channel config, which is supported on my receiver. Most of the time the surround sound is fine but it spontaneously it seems to lose the surround decoding and the center channel and surround channels disappear and only the front left and right continue to play sound. So I end up with basically no dialog sound and just some ambient sounds from those speakers. Sometimes a restart of the xbox fixes it, sometimes it takes a few restarts, sometimes I have to switch it to bitstream to get the sound back. I don't like using bitstream though since anything with 5.1 channels puts the rear out my side channels. In the 7.1 PCM config the rear sounds from a 5.1 source comes out my rear speakers they way it should.
The problem doesn't appear to affect other apps since I haven't ever experienced the issue while watching Netflix.
I know it isn't a Plex server issue since I also have a roku and iPhone and iPad devices and they don't experience the audio glitch (although they are only two channel transcoded devices so maybe they wouldn't experience the issue at all in that config).
Anyways, there have been lots of gitchy behavior lately with the Xbox One Plex app. I too experienced the video sync issue and had to turn off that one setting specified in another thread. I am also experiencing the buffering issue periodically where it just buffers forever and I need to stop then resume my video to continue. I also have one movie that was partially watched and I then subsequently marked it as watched and saw it disappear from the currently watching list but it eventually just shows up again. All of this with in the last few weeks for the most part.
I am also a Plex Pass subscriber and am on the latest server and app versions.
If anyone has any insight it would be helpful.