This issue has been reported a lot over the past 6 years, but didn’t been fixed yet.
In the Hebrew subtitles the punctuation are displayed reversed, for example:
Correct: ?שלום, מה שלומך
Wrong: שלום, מה שלומך?
Correct: Hello, how are you?
Worng: ?Hello, how are
This issue happens when in external srt files (with and without .heb in the filename) and also in embedded subtitles in mkv file.
The only way to resolve this is to burn the subtitle, but this make the video to be transcoded and not direct stream/play.
All the Hebrew subtitles files are getting fixed by reversing them to RTL to be able to play them in all Players, this is the way to support all players, but only Plex doesn’t follow that way and i think that for the Hebrew language it tries to reverse it to “fix” the Hebrew RTL problem.
I think that you need to add an option to reverse RTL languages that the user can activate, so that we can control when the subtitle file is not reversed.
Here are some posts that this been reported