Sonarr occasionally fails to rename episodes downloaded via Transmission

Sonarr version (exact version): 3.0.10.1566
Mono version (if Sonarr is not running on Windows):5.18.0.240
OS: Raspbian GNU/Linux 10 (buster)
transmission-daemon 3.00

Occasionally, Sonarr fails to rename episodes it downloaded using Transmission. The episodes will just sit in the download directory. The download directory (/media/Media/Video/downloading/sonarr) is on the same mount point as the destination directory (/media/Media/Video/TV).

This behavior is not limited to a particular series; episodes of the same series sometimes transfer OK and sometimes do not. The destination directories are owned by nobody/nogroup. Downloads are owned by Debian-transmission, but the sonarr user is part of the Debian-transmission group, so there should be no permission issues.

Logs don’t really show any errors/issues. I have the log level set to debug, but neither log shows anything unusual.