FORGED_HOTMAIL_RCVD bug??

[Jeremy Fairbrass <jf...@hotmail.com>]

G'day everyone,
I received a legitimate email from Hotmail today, which (I believe) 
inappropriately triggered the FORGED_HOTMAIL_RCVD rule in my SpamAssassin 
(version 3.1.5). The email from Hotmail was actually a bounce-back to an 
email sent by one of my users to a Hotmail address - it was bouncing back as 
a "no such user" error from Hotmail, but I think that's not relevant.

There were only two Received headers in the email from Hotmail, and they are 
as follows (unchanged except for the munging of mydomain.com). The top-most 
Received header was added by my server, and is therefore reliable, as is the 
Hotmail IP stated there - 65.54.246.140. Can anyone tell me why the 
FORGED_HOTMAIL_RCVD rule misfired, and what I might be able to do about 
it?....

----------------------
Received: from bay0-omc2-s4.bay0.hotmail.com (bay0-omc2-s4.bay0.hotmail.com 
[65.54.246.140])
 by mail.mydomain.com (mail.mydomain.com [87.230.126.33])
 (MDaemon PRO v9.5.0gm1)
 with ESMTP id md50000068214.msg
 for <us...@mydomain.com>; Mon, 16 Oct 2006 10:25:51 +0200

Received: from bay0-mc2-f7.bay0.hotmail.com ([65.54.244.47]) by 
bay0-omc2-s4.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.1830);
  Mon, 16 Oct 2006 00:52:09 -0700
----------------------

Cheers,
Jeremy