I'm home now so I could use the original link. It looks like it is trying to extract the subtitles but failing. Do your files actually have subtitles? Does this happen with every file or just a few files?
Jellyfin 10.10.1 (Docker)
Ubuntu 24.04 LTS
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
3x WD Red Pro 6TB CMR in RAIDZ1 (JF Library)