Can't manually add artwork to Music (iTunes for Mac)

turingtest2 - thank you! The problem, inexplicably, was the Airplay thing you mentioned in that linked document. While this solved my immediate problem, it's clear that this should be considered a bug in the Music app. Thanks so much for the assistance.

AirPlay

iTunes, or Music in Catalina, might not be able to save changes to tags while AirPlay is active.

Hi chrisg_01 - thanks for your comments and clarifying questions. Some responses:

"To clarify, is this happening with one specific song, or does it happen with all songs?"

I am unable to add or update album art on any items in my library. In testing this more, I also realized that I apparently can't update any metadata. For example, I attempt to change the name of the song. It initially accepts the change when I close the Get Info window, but then subsequently reverts to the old song name.

"Try clicking the artwork that you see currently in Get Info > Artwork, and then delete it. Then try re-adding it. Does that work?"

There is no artwork initially, so there is nothing to delete.

"Have you tried clicking Apple menu () > Restart and testing again?"

Yes, restarting the computer does not resolve the problem(s).