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2) is the person showing up in a normal OWA search. if they are, then it is a problem with the local mail client and not the global address book.
I don't believe you, there is something wrong with the OAB and the GAL!
Here are some things you can and should check if you think there is a problem with OAB and the GAL. Note, admin privs may be required.
Check Sync Errors in the Client
Check for Connection Errors with the Client and ensure "Directory Service" is connected
Check whether autodiscover resolves the OAB URL
Check in Exchange Management Console for the last GAL Publish Date (it should be todays date between 4am and 7am)
Check in Exchange Management Console to ensure that all CASHUB servers are publishing the GAL
Things to keep in mind
People join the university in waves, often at the start of semesters.