1 Bad Apple (no pun intended)

Hello.

I have 1 user in my enterprise that can't see his groups in either the desktop app or OWA.  I've given myself permissions to his mailbox.  I can't see them in his mailbox either.  It's not that the Groups are is empty because he isn't a member of any groups.  He's a member of about 15 or so.  The Groups section of his mailbox just isn't there.  

Any ideas would be appreciated.