Server Version#: 1.41.4.9463-72009463
Player Version#: 8.45(1)
i have been using the combination of Synology NAS with Plex Media Server, AppleTV 4K and Bose Lifestyle 650 - all working fine until the latest Plex on Appletv update to 8.45(1).
Under the audio options, default Audio only show TV Speakers, under the option for Temporary Audio Output i can select Lifestyle 650.
when i do this and then try to do playback in Plex, sound comes from the Lifestyle 650. but video stops and forces the Lifestyle to goes into setup mode - but does not reach the setup screen…
All other apps on the Appletv are working fine with the Lifestyle 650 (e.g. other streaming apps)
i solved the problem after 3 days of trial and error, seems the latest upgrade reset some settings, after going through every single setting and resetting the appletv it now works.
I have a near identical setup and just started experiencing similar issues as you described. Do you know which settings you had to update that can help narrow my focus?
when the last update happened on Apple TV, it reset all the settings, and i had to set sound back to 16bit… i think this is what did it… if this does not work, please let me know and i will have another look at my end.