>   One of the Autocat subscribers has reported an instance of a related but
>somewhat different problem.  He send a message to Autocat which was
>distributed in normal fashion.  He then received a message from LISTSERV
>saying that his posting to the list was being rejected as it had been
>previously posted.  He swears he had not attempted to re-post his original
>message and I have no reason to doubt him.
 
If the message was distributed to the subscribership,
then I would assume that some mail transport agent
had attempted to send the original posters one message
twice to the list.  LISTSERV, not knowing that the
MTA was retransmitting the original, said "whoa, duplicate."
 
(I wonder what ListProc would have done? ;-) <rhetorically asked>)
 
/P