PGS can be played directly without server transcoding but .ass can't be displayed
I have a SONY Xperia XZ Premium. After installing the latest PLEX client, I was pleasantly surprised to find that I can directly play video with PGS subtitles directly on the phone, but the external ASS files can't be displayed without burn in. If I revert to the old plex version, ASS words and don't need to transcode but PGS need.
I also have IPHONE X, ipad pro, apple tv, shield tv, roku, fire tv, nexus player... All plex clients have a variety of issues.