FTV 4k has a number of issues… The Android ExoPlayer has issues…
If you sideload or are running 7.27.1.15203 or lower of the Plex client you can go into setting and disable use new player.
There are new beta versions of the Plex client, 7.30.0.16150 seems to work. there is a new one just haven’t had time to load and test. They seem to work with the new player if you upgrade the FTV 4k itself…