I had several issues with Subs, and it appears that is a recurent issue.
However, i noticed that the PMS on Shield is storing subs in : Android/data/com.plex.mediaserver.smb/plex media server/Media/localhost/#letter#/#bundle ref#/contents/subtile contributions/#bundleref+srtfile#…
instead of
Android/data/com.plex.mediaserver.smb/plex media server/Media/localhost/#letter#/#bundle ref#/contents/subtile/en/#srtfile#
ths generates the following error on PMS :
Couldn’t find the file to stream: /storage/emulated/0/Android/data/com.plexapp.mediaserver.smb/Plex Media Server/Media/localhost/d/2b59b5c51bf81d32df9a4928c6458bb6117b62e.bundle/Contents/Subtitles/en/com.plexapp.agents.opensubtitles_70a0d649fd0f8e6718a78fe9e3e79c2252866346.srt
and
[Transcoder] /storage/emulated/0/Android/data/com.plexapp.mediaserver.smb/cache/Transcode/Sessions/plex-transcode-oeg904hdt0l19dpzhi63tlf0-7762b3a9-bb57-4372-91c5-d390cca909c6/temp-0.srt: Invalid data found when processing input
PMS version is Version 1.14.0.5465