This is on two different pieces of hardware using the same media. One is a Lenovo m73 tiny. That's an Intel Core i3-4130T, Integrated: Integrated 2013 Intel HD graphics, 8GB system RAM. The other is an HP Elite Desk 705 G3 Desktop Mini with an AMD A10, AMD Radeon R9 graphics, 8GB RAM.
We are running LibreELEC, v9.95.1 10.0 with kernel: Linux 5.10.21 on both hardware.
I do not yet have access to a debug log I will provide one when I get to my Lenovo and have access to create one. Then I will edit a link to that log here.
The issue: If you start a show with subtitles they will display as normal. However if you pause the show or rewind it the subtitles will be disabled when you attempt to resume watching. You need to access the subtitles menu and re-enable them to get the to display. The same thing seems to happen if you rewind a show and resume playback.
To reproduce, have subtitles with the video, start video after some time pause video. Subtitles disappear. Re-enable subtitles within the video. Play video for sometime. Rewind video, subtitles stop playing. Open menu, subtitles are disabled again.