> How would a downloaded file buffer

I've no idea. It happens sometimes and only seems to happen with certain fils. In this case I'm sure it's a jellyfin issue, but this just comes down to having to debug while someone is waiting to watch - which is exactly the time I don't want to.

As for language/subtitles it's true if it happens from the start (which I agree, is usually true) but occasionally the downloads get weird midway through.