Subtitles not working on Roku Jellyfin app

I’m having an issue with subtitles on my Roku while using Jellyfin. When I play an episode of a TV show and turn on the subtitles, they don’t show up. If I press the * button and set “Captioning always on,” they still don’t work. When I exit and reenter the episode, the “always on” setting is turned off again.

I’ve repeated this process many times with no success. The episodes are MP4 format with SRT subtitles. I know apps sometimes override subtitle preferences, so I’ll also be posting this on the Jellyfin forums, but I suspect it could be a Roku issue. Has anyone else experienced this or found a fix?