Assume that you enable mailbox audit logging for a shared mailbox that's delegated to you in Microsoft Exchange Server 2013. When you send an email by selecting the shared mailbox in the From field, Send As audit events aren't logged as expected. But the event ID 2005 is logged in the Event Viewer. The event ID 2005 looks something like the following:
This issue occurs because the user and the mailbox are located in different Active Directory sites.
To resolve this issue, install Cumulative Update 10 for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.