Deletes "Gotham", Every Night

Every night my PMS deletes one particular TV show (Gotham, two seasons). The show drops from the library and the files are in the trash bin. Every night. I reload it from a backup in the morning, Plex deletes it that evening without fail.

I try to be a good Plex citizen and follow best practices. And I’ve mostly had a great experience but this has me stumped. Any help is greatly appreciated.

Log files from last night’s “purging” attached. I run PMS version 1.9.4.4325 on a Macintosh with macOS 10.12 Sierra. I have unchecked “Allow media deletion” in Library Settings. My media is all loaded on an external 8TB USB 3 drive. As far as I know, this is the only weird thing happening.

What am I doing wrong?