Server Version#: v1.23.5.4862 on QNAP TS251D (had this issue on all versions I have used)
Player Version#: 8.19.4.26157 (Fire Stick 4k)
Tuner Make/Model: HD Homerun Connect DUO
Guide/Lineup name: UK Terrestrial TV via Plex
Using XMLTV?: No
Channel number/Name: All
I have the above setup so I can have TV in another room. I don’t have any issues with picture, buffering etc but I have always had a issue with the audio going out of sync with the video (Audio lags behind).
This can be resolved temporarily by going back 10 secs and then forward again, but it will desync again within a minute. Should also note the desync gets worse over time.
I have the same issue: my Plex Server is on Shield. It’s especially pronounced when watching Live TV. If I look carefully, I can see that after about a minute about half a second’s worth of frames are dropped and then the same happens a minute or so later. On each occasion the audio moves further out of sync. Rewinding has some affect but not sufficient to address the issue. Eventually the entire playback stops saying an error occurred. It looks like it’s something specifically to do with the 4K version of FireTV. @sa2000 are you seeing same?
I haven’t tried playing other media as the Firestick is in place specifically to provide TV in that room rather than running a separate aerial feed. However, I will give it a test on other media and see if I see the same.