First time to try is resetting the FSLogix profile and making sure that there are no profiles left over on the local host from the user that is being affeted.
This issue is normally either the users profile is corrupt, or there is a c:\users\local_USERNAME directory left behind with a file lock. Maker sure that local directory does not exist when the user is not logged onto the host.
We recently raised a support call to Microsoft after this issue surfaced for a single user back in December 2020 and the response back was: "it's a known issue and will be fixed in a future update" (no date given).
Microsoft haven't explicitly said what triggers this issue, but we have assumed it's a bug with the FSLogix agent.