There's a couple possibilities that come to mind here.

First, the after hours path by default is to go to the Example Interview Handler which takes messages that are left for the Example Administrator account. You can either change this path or change the recipient.

Second, the unaddressed messages distribution list is, by default, populated only by the Example Administrator account (you should have "live" admin types in here) - Any message that is left by an outside caller to a mailbox that's full or any message that cannot be delivered due to network problems or issues with the Exchange mailstore etc... get redirected here.

If I had to put money on it, I'm guessing the messages are coming via the example interview handler.