Hello,

I use the v3.5.3.660.

I received a mail with bad header information (I substituted some information with ... )  :

Received: from ...
Received: from ...
Received: from ...
Received: from ...
To: ...
From:...

Reply-To: ...

X-Mailer: ...

MIME-Version: 1.0

Content-type: text/html; charset=iso-8859-2

Message-Id: ...
Date: Mon, 23 Apr 2007 12:15:20 +0200 (CEST)
X-Server: LogSat Software SMTP Server
X-SF-RX-Return-Path: ...
X-SF-HELO-Domain: ...
...

As you can see the header is broken with blank lines (or sometimes lines with a single space character). As I know the header is ends with a blank line. So the text starting with Reply-To is not part of the header.
But SF processes it and the following lines as the header and inserts its information into the message body.

We receive spam messages in this format regulary and the mail filter at the client cannot detect it because the X-SF-SPAM field is in the body not in the header...