The address is like this:
This NDR is generated by Exchange 2003 server.
It is in 50% of all mail sent to contacts.
It must be something with X400 handling.
This sounds very much like a known problem in Outlook 2000 in SP3 and earlier. This problem occurs because the Microsoft Outlook client improperly formats the MDBEF encoding. In particular, Outlook may include the PR_EMAIL_ADDRESS MAPI property in a non-recipient context when an e-mail message is forwarded after a rule has moved the e-mail message to a different folder.
This problem has been fixed in the Outlook 2000 Post-Service Pack 3 Hotfix Rollup Package from June 7, 2003. For details on how to obtain this rollup, see Microsoft Knowledge Base article 822612, "Availability of the Outlook 2000 Post-Service Pack 3 Hotfix Package: June 7, 2003."
This was first published in April 2004