We have a strange problem. We've migrated cross forrest from an Exchange 2007 to an Exchange 2013. Everything seems to be ok, except for one issue we have which is that sometimes an email sent to a distribution group is received 15 minutes later by 2 - 3 of the users within the list.
The list contain 42 members, and I can see that the email is "sitting" on one server for the 15 minutes in question by reading the header of the email. The problem is not consistent.
Expansionserver is $null on all of my distribution lists, and I can have issues on other lists aswell, although that might just get noticed.
If I try the tracker tool in EMC or through the gui (ecp) I get a "to many items in array" error. So I can't see anything in my exchange shells either.
All the users in the list are in the same domain, but the users are spread across 2-3 exchange servers. The server that the mail is "sitting" in, oddly has 0 of the members within the distlist.
any advice as to where to look is appreciated. if it is a problem with the expansionserver I would be greatful for any steps to find out how that can be determined or even better, be resolved.