[ms office - 2003] Outlook sending emails next week?!

[OutToLunch]

Well, this is a Friday afternoon weird one. I have an email account/user here who's Sent Items in Outlook is showing various emails sent under a heading of "Next Week" - in the same way it would normally have "Today", "Yesterday". They won't settle for my explanation that Outlook is being extra efficient and doing next weeks work for them...

 

I've checked all the obvious things - Exchange server date/time is correct, users laptop date/time is correct, emails showing as Next Week have definitely been sent and have been confirmed received by the recipients. Any ideas? I'm stumped!