After hitting play I get a black screen, the video thinks its playing as time is going forward, and I also see subtitles, but no image or audio is present until I press back and restart the video (or go to quality and change from Original to Auto). According to Tautulli, the audio, video and subs are all being direct played.
This affects files randomly, be it h264, h265 3mbps or 15mbps. TV is connected via 1000Mbit ethernet and server is in the same LAN. Plex hosted on Windows 10. It almost feels like if the server won't start transfering the video quickly enough (HD spinning up) I get the black screen. After the blank screen I can usually change to any episode of the affected series and playback works instantly.
This issue does not persist if I play via files on the PMP, Chromecast or last years Samsung (Tizen) tv.