Thanks for this information. You can use the Graph Explorer to run a query to verify what information this plugin would read from the system.
In our case, we believe that there is some other error going on with the user account that we’d like to remedy rather than attempting to switch to the userPrincipalName. Although the account looks good on-prem, the cloud synced account doesn’t look right. We’re behind on our AADConnect version, so we’re updating that to see if it helps.
Thanks again for the help and the pointers!