I have had 2 reports of the past month or so where a user suddenly receives mail from a month or more ago. These do not appear to be old messages form the "I have already seen them" point of view. These seem to be unseen messages that are a week to a month or so old that are suddenly delivered. I am not sure if this is an Outlook issue or an Exchange issue. It is Exchange 2010 and Outlook 2010.