Can you provide some additional details so people can attempt to replicate?
Plex Media Server version? 4.108.0 is Plex Web. Look in Settings → Server_Name → General
Plex client & version?
Is this
- Live broadcast TV using a tuner (live tv & dvr)
- TV show recorded using a tuner (live tv & dvr)
- Free streaming TV from plex.tv (live tv streaming)
- A TV show stored on your server (playback)
Do you have subtitles enabled? If so, might it be this: Conversion failed playback error when subtitles are over (usually at the end) ?