@entropicdrift@lemmy.sdf.org the server has been there for ages, but I added new content, which has been scanned weeks ago. It only happens when I play it, so that is why I'm curious.
In particular I was wondering if that will happen if running a server without internet: Will it fail fetching whatever data is fetching in that case? If it the subtitles for example? If so, I'd like to download the additional data while I still have Internet access, but without having to click every single file.
Jellyfin doesn't fetch data from the web outside of its scans, generally speaking. Probably this is a case of your cache being slow or your video needing to be transcoded. I've used my server when my internet was out several times and never had an issue.