Solved: changed Burn Subtitles (Direct Play Only) from Auto to Always
Dunno, but posted it on plex forum too.
Plex for Kodi add-on 0.1.6 subtitles (SRT) NOT working.
All subtitles (SRT and SRT/embedded) not showing with latest Plex for Kodi add-on 0.1.6 in LibreElec v8.95.2 for Pi 3 A+.
Is there something I need to change in the configuration ?