Blank lines at end of message ?

I have a strange bug in which every message to a list has six blank lines 
added at the end.  The messages come via a script that mails them to the 
list, and the blanks aren't there when it mails them.  The list is 
otherwise a rather ordinary moderated list.  The message_footer is empty.

Any ideas where to look?

Regards,
John Levine, [email protected], Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor
"More Wiener schnitzel, please", said Tom, revealingly.