What mailer are you using / how is it set up.
 
I did not do the installation, but we are running LMAIL here and if
there are ANY header errors, the item goes to POSTMAST and other
designated Ids and nowhere else.  This includes items with multiple
( even if exact duplicate ) "From:" headers which used to go thru
under our previous MAIL handler.  Do we have things screwed down
unusually tight ?? It DOES seem catch a lot of potential problems
before they get into the listserv stream ...          - Mike