Anybody seeing similar?
If select SRT subtitle before beginning movie, then subtitles display correctly.
If select SRT subtitle after movie begins (none -> SRT External), then subtitles do not display. If then stop & restart playback, subtitles display correctly (like when selected prior to playback).
This happens with both MKV & MP4 containers. Embedded subtitles, PGS (MKV) and MOV_TEXT (MP4), do not have this problem. They display correctly whether chosen beforehand or during playback.
Following Plex naming conventions:
movie (year).mkv
movie (year).eng.srt
Plex Client 6.17.0.4579
PMS 1.13.0.5003 on Shield TV & Windows 10
