An administrator observed that if an Exchange Mailbox is exported to *.pst from the 2013 Exchange Admin Center Change Auditor captures the Mailbox name as a GUID (figure 1). This condition is also reflected in the Windows Event Viewer MSExchange CmdletLogs well, (figure 2).
However when the same event is executed in the Exchange Management Shell (New-MailboxExportRequest), the mailbox name is recorded correctly in both Change Auditor and the MSExchange CmdletLogs, (figure 3 and 4).
Providing the GUID in lieu of the Mailbox name it the normal behave when a mail box is exported to *pst in the Exchange Admin Center. This is a function of the way the command is processed in the EAC.
A feature request was created to conduct a more thorough research and provide a solution targeting a future release date not yet establish.
The likely approach is to create a specific Event Class then resolve the mailbox name using the GUID when the event is triggered.