We've had issues with subtitles sync with TV shows for a while now, even though it used to work perfectly. It is really weird as we experience several different variations of the problem:
• A few times the subtitles run fine and in sync with the TV show.
• Sometimes they run too slow or too fast. In very few cases the subtitles even manage to slowly correct themselves during playback, so they are in sync at the end of the episode.
• Sometimes Plex shows a subtitle which doesn't belong to the episode in question, but another in the same season.
It doesn't matter if the show is wrapped in an MKV, AVI or MP4, or if transcoding is required or not. We only use external SRT subtitles. Movies don't have this problem.
Server has been running 22.214.171.12433 for quite a while, due to the bandwith problems people talk about in the forum, so the problem doesn't lay there. We've definitely had the problem with Plex 1.9 and 1.10 on the Apple TV, but I can't say for sure if the problem started with 1.7 or 1.8.
I'd like to hear some feedback! :)