Thanks. The items that appeared here were created in 2022 (when I set up these work accounts in my "Work" vault).

When I have 'Offline Items' selected, pressing the Cloud button with slash results in brief animation, like its syncing, and then the original error shows. The items stay as-is, there is no change.

Good news is, I have gone through them manually and don't think I have lost any data (they seem identical, but duplicated, in the Work vault).