Just as with Xbox One Plex, Plex for Series X drops subtitles and buffers for me (on every xbox in the house). I was really hoping the Series X would fix the problems. Hard of hearing so I depend on the subs. I have a new computer built by my son-in-law (A senior computer engineer) to be a Plex powerhouse server. All other local and remote clients (android, smart tv, ios, etc…etc.) play perfectly.
PLEASE PLEX; FIX THE XBOX CLIENT
Latest Server and Client Versions