Reading through this, I realize that I too had this. I then recalled that I turned off Convert Automatically on on CCwGTV and it stopped.
But I am seeing plex decide to do some odd things with Subs when using the Android client. Like Burning SRT subs when the TV doesn’t support HDR but the Device doing the actual streaming does. Not sure if they are related but I started this thread about it 4K HDR Transcoding on 1080 TV - Plex Players - Plex Forum
