Restored emails appearing on Blackberry

I've got an issue with one particular user's Blackberry when performing a Restore task. We've recently had to run a restore task for all email for several user mailboxes. When the restore task started to restore the one person's emails, the user's blackberry starting displaying a large number of the restored messages (all of which happened to originate from his Sent items folder). We then shortcutted the emails and then ran the restore again, only to get the same problem. Anyone ever see or hear of this problem? Any suggestions as to how or why this could happen?