Did you perhaps add some albums from Tidal or Qobuz to your library recently?
I had the same issue yesterday, whilst Roon was suffering from the Google Cloud Services downtime.
I had added 3 albums in Qobuz. All 3 were added but only album title was specified ( no cover, unidentified).
I have deleted the 3 albums from my library, and shut down my Roon server machine completely.
Restarted this morning. No error mesages anymore.
Re-added the same 3 albums, everything went smoothly.
I would in any case restart your roon server completely, without starting try8ng to cure the problem.
It will cure itself
Dirk