I think I figured out how to do it. I just removed the movie from Plex (moved it temporarily to an Extras folder), ran Optimize Database and Clean Bundles, and then moved the movie back into Plex. It seems like that reset it and caused it to start using the subtitle settings in Audio & Subtitle Settings.
A bit of background. I was playing around with tagging forced subtitles in the MKV, and specifically what happens if you tag multiple subtitles as forced (each language has their own forced subtitle). In testing this in Plex, I discovered that after manually selecting a subtitle and then switching the subtitle back to None for the movie in Plex, it was no longer showing the forced subtitles automatically. That is when I came across the above article explaining why that was happening. After “resetting” the movie, it’s now showing forced subtitles again even when subtitles is set to None.
Follow up: I forgot to mention that I also scanned the library after removing the movie, but before optimizing database and cleaning bundles. I guess you could say I did a semi Plex dance, but it only took a few minutes and wasn’t a big deal.
