Unsolved. Nothing logged that would explain the behavior. A theory provided by another mod/dev is that some internal OS queue is being maxed out. Caused by slow I/O. A slow CPU, kernel bug? Hard to say.
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