When you make changes to the metadata of a file in Jellyfin, AFAIK, it never applies it to the file. Not that it could on my setup since Jellyfin has read-only access to my files.
Jellyfin 10.10.7 (Docker)
Ubuntu 24.04.2 LTS w/HWE
Intel i3 12100
Intel Arc A380
OS drive - SK Hynix P41 1TB
Storage
4x WD Red Pro 6TB CMR in RAIDZ1