When I try to watch foreign audio MKV videos on Roku Plex, then the subtitle stream only works for a scant few seconds. Then Plex stops showing dialogue.
Initially, I thought the problem was the subtitle track. So I used the subtitle search feature to experiment with alternative subtitle tracks for the same video. But they all exhibit the same exact bug. With each new subtitle track freshly selected, they show a few lines of dialogue. Then just a few seconds later, nothing.
This problem does not happen with the Web (macOS Google Chrome) Plex player.
This problem happens with many different videos.
The problem has been happening for many months.
Using the latest stable Plex release installed via snap on Ubuntu.