I have some Outlook users who are saying that sometimes during the day they'll suddenly get a spurt of email into their inboxes. The mail in question appears to be several hours old. I have researched the logs on the server and looked at the header of one of the messages. It appears to me that mail is being delivered in a timely fashion (see my posting in the administrator's forum about verifying my assumptions: Perceived delay in message delivery)
Assuming that I'm right about mail being delivered to the users' inboxes as soon as it hits the server, the problem would appear to be with the Outlook Connector. The users report that the Connector seems to be working fine when they do a Send/Receive. Most users are using the pre-release 4.5.7 Connector.
Has anyone else seen similar behavior?