2024-06-13, 09:35 PM
The Jellyfin flatpak is not officially supported and has been known to cause issues. Your best bet is to reinstall using the recommended way under Arch/derivatives. That said, even the Arch package is maintained by Arch packagers and not the Jellyfin team; it can lag behind sometimes and any issues should be reported to them first.
As for the flatpak, just taking a guess here, it sounds like some sort of permission problem, perhaps paired with an inability to transcode incompatible subtitles for whatever reason. Some remuxing could be happening when direct streaming and that also can remove subs. If the problem persists even after reinstalling using the recommended way I mentioned before, more information would be helpful to identify the problem such as your server specs, version of Jellyfin installed and logs, particularly any ffmpeg logs in which the problem occurred.
As for the flatpak, just taking a guess here, it sounds like some sort of permission problem, perhaps paired with an inability to transcode incompatible subtitles for whatever reason. Some remuxing could be happening when direct streaming and that also can remove subs. If the problem persists even after reinstalling using the recommended way I mentioned before, more information would be helpful to identify the problem such as your server specs, version of Jellyfin installed and logs, particularly any ffmpeg logs in which the problem occurred.
Server specs => OS: Debian 12 | GPU: Arc A380 | CPU: Ryzen 5 5600X | 64GB RAM | 56TB