Sometimes qobuz change the underlying master used and this breaks links in Roon especially if it’s been grouped with a local or another version. Can you show the contents of the versions tab for the album this may give a clue.
My problem started when I did a database Restore from a Backup that was taken 2 days before the addition of 4 albums. Two albums I could delete and two I couldn’t.
Is the album you are trying to remove still in Qobuz Favorites?
The two I couldn’t delete weren’t, i.e. evidently they were removed the first time I deleted them from within Roon., but they still showed up in Roon and I couldn’t delete them.
Finally some combination of re-syncing with Qobuz and restarting the Core (restarting the entire Core not just the Server) worked.
Thanks guys. Amazing. Something so simple as switching off the nucleus with its power button and then switching on again did the trick! I should have tried that before!