One additional note:
Your screenshot shows you’ve selected to display English forced subtitles. However, the file only lists the regular subtitles (no forced track).
Not correct. I have the same setting and my full English subtitles are selected either when the media only has a foreign audio track or if I select the foreign audio track when there is an English track available.
Also, forced subtitles are selected when the audio track and subtitle track (labeled forced) match. That would not apply in this case.
Also, I will note this is the official Plex Docker image (not linuxserver.io).
Edit: I hadn’t checked programs that have forced subs, so I just now added additional content to the test library. It doesn’t appear forced subs are being selected either.
Checking back in on this issue on the server, the problem seems to have self-resolved.
After looking at multiple shows just now:
Foreign-language shows are now showing the English subs as selected.
Shows that are English language with a forced subtitle track also have the Forced subs already activated when first opening an episode’s page.
Shows that have multiple audio tracks are changing the subtitle track between Forced or Full subs when I select either English audio or a foreign audio track.
Glad you were able to “figure” it out (aka, it started working out of nowhere). Sorry I did not respond back. I was not quite sure where to go next and just had not had time to come back to this also.