PGS subtitles not showing on few movies

[RafterX]

I have a remote plex user, where the PGS subtitles is not showing on the movie: Last Breath(2024) and on Ghost Busters: Frozen Empire(2024). But subtitles are showing fine on others, like The Flash(2023), extracted with MakeMKV in the same way, and all are Blu-Ray movies. She tried on the Plex app on the TV, and the Chromecast from phone app.
I have no issues with the subtitles, and never had.
We checked that the subtitles are enabled on her clients (only one language option as I have only chosen my own language subtitles to go with the movie).
What is wrong?
What more should she try to do? Would I be able to see anything in the logs, if I enable advanced debug logs?

You need more info, let me know

Thanks for any and all your help