Using Exchange 2003...
User gets his e-mail using his laptop using both OWA and Outlook using http.
In the office he uses a workstation with Outlook to get his e-mail form the same Exchange server.
His OWA and http Outlook connections are providing him with e-mail that was deleted years ago.
His office workstation Outlook is still looking and working normally.
This is the only user that I know of with this issue...