Error syncing Music library: Missing movie files

I have an iPad and iPhone that I sync music to from my Mac. This goes without issue when I just select certain playlists. However, when I try to sync my entire music library I get an error about certain files being missing.

The weird thing is that the error mentions movies, not songs! And the movies are movies I once had, but not anymore, but I get these error while syncing movies isn't even turned on.

When I search for the name of the "missing" movies, I don't find anything in the TV library or the Music library. I even made a completely new Music library, but the problem keeps coming back!

I am currently on iOS 18 / MacOS Seqoia, but it has been going on for several software versions now.