Content-Type: text/plain
Content-Disposition: inline
Content-Transfer-Encoding: binary
MIME-Version: 1.0
X-Mailer: MIME-tools 5.427 (Entity 5.427)
RT-Send-CC:
X-RT-Original-Encoding: iso-8859-1
Content-Length: 74

This problem was previousl reported (#6643) and was already fixed for 1.8.