I was getting a similar issue (and error message) a few times last week. Tidal was logging out and I had to log in again. I realize the OP is referring to Qobuz, but I would check the streaming services settings and see if anything is amiss. When the streaming service wasn’t logged in the tracks became unavailable.
This issue seems to have rectified itself on my end.
Checking in on this thread, are you still running into issues here? If you head into your services settings, and manually sync your Qobuz library, do you run into the same issue? Does rebooting your core device result in the same issue?