User ID displayed instead of user email, for ONLY one of our users

[Linda Walmer]

We have Jira Server, and use Active Directory.  We have Adaptivist Test Management for Jira add-on.  In the add-on, when we assign ONE particular user to a test, then generate a document, instead of displaying the user's email name, it displays ID12365, 

Any idea what might be wrong?  We've done a manual sync with Active Directory, pulled him out of groups and put him back in, etc.

Thanks!