Recently ran a migration from a 2003 Small Business Server to a 2008 Small Business Server. The migration has been largely successful, with most compatibility issues resolved in short order.
Noticing something strange regarding distribution groups, however; this was spurred by a number of complaints from end users.
Specifically, if an email is sent to an internal distribution group, the messages aren't actually received by the recipients for 10 to 30 minutes.
If the individual constituents of the distribution group are emailed, the message is received instantly.
The server isn't generating any exchange events at current, the senders are not receiving delivery delay notifications, and the messages are received initially.
I am trying to determine the cause of the delay. Has anyone seen this behaviour before?