Version:           ukendt (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu18 dapper)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.15-23-386

After upgrading my Kmail I have started to see corrupted headers like:
--------------------------
X-KMail-EncryptionState:  
X-KMail-SignatureState:  
X-KMail-MDN-Sent:  

To: "Sune Rastad Bahn" <bahn@mistics.com>
Subject: artikel
-----------------------
(email-adress edited for anonymity )
Notice the blank line just after
X-KMail-MDN-Sent:
and before 
To:
This breaks the header and make the letter appear funny in the viewer.

Usually corrupted header is due to MTAs but in this case the header is corrupted before the "To:" so it is hard to believe it would make it to my inbox, unless it happened after the delivery. My suspicion that it is Kmail doing the unfortunate header rewriting is also raised by the fact that the headers just above the blank line are all related to Kmail.