Subtiltles syncing okay in one computer but not in another?

Hi, I just set up my media server last week with YAMS and everything is working amazingly. The only problem we're having is subtitle syncing, for example we downloaded the latest season of Gen V and with the same selected subtitles on Jellyfin, my flatmate has their subtitles synced and mine aren't. Does anyone know what could be the cause of this?

Thanks a lot!