Latest versions of the server and player. When I am playing a show (in this case, The Love Boat, (recent The.Love.Boat.1080p.WEB-DL.AAC2.0.H.264-squalor versions) the embedded subtitles (shows as SDH type) are not playing in sync, it is quite far ahead, several seconds. They also cannot be moved inside Plex, the offset is greyed out.
However, when I play the same file in MPC-BE, it works fine.
FIle info from MPC
Video: H.264/AVC 1280x960 23.976fps [English, AVC [Default] (H.264/AVC, High Profile, Level 4.0, 1280x960, 23.976 fps)]
Audio: AAC 48000Hz 2.0 chn [English, AAC (Audio 1) [Default] (AAC, 48.0 kHz, 2.0 chn)]
Subtitle: UTF-8 [English, English (SDH) (Subtitle 1)]
I have not had this issue with other files.