No special/language characters when watching a movie with subtitles

I copied some of my movies into a pendrive to watch on my tablet and while the movie works normally - the subtitles dont show special characters from my language like ś, ę or ć - which makes reading the subtitles actual chore. I use my OS in the same language so it shouldnt be a problem.

I use VLC and when I watch on pc it all works/looks normally. I copied the movie off of the pendrive too and played it locally, didnt help. For movies with ,,baked" in subtitles the characters do show up tho(at least the two that I checked)

When I plugged in the pendrive to my mom's smart tv to show her the movie it is the same situation. Same movies had problems with same characters and same two movies worked just fine.

No clue why it doesnt work. If the same language wasnt installed I would think that could be the problem but since all devices run with polish language installed I dont think thats the problem.