Do you have other apps accessing and or modifying the file? I'm not sure why files on your C drive would become inaccessible unless another app was modifying the file.
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