My Android Plex players are unable to resume playback when subtitles are enabled. Playing from the beginning with subtitles enabled works, but with a noticeable delay. When subtitles are disabled, resuming is possible without any problems and there is no delay in playback. After that, it is possible to turn the subtitles back on. The format where I could find this error is a .mkv and the subtitles are embedded. I am only experiencing this problem on Android devices. IOS devices are not affected by the problem.
Plex Player (Android): Version 8.12.3.22809.818254225
Plex Player (Fire OS): Version 8.8.1.21332
Plex Media Server (Linux): Version 1.21.2.3978