I have an Exchange 2010 user that has a weird problem with their email. When new email arrives, it sits in the Inbox for anywhere from a few seconds to a few minutes and then gets moved to a folder called "Junk". This is not the default "Junk E-Mail" folder, but a new folder. If you move everything back into the Inbox and permanently delete this "Junk" folder, it gets recreated when a new email arrives. There are no rules setup on the mailbox.
This is happening both in Outlook and Outlook Web Access. I've run a full virus scan on the PC and run a repair on the Exchange mailbox. Does anyone have any clue what this could be and how to stop it?