[Mailman-Users] Weird subject_prefix issue

[Stephen J. Turnbull]

Mark Sapiro writes:

 > My guess is that this one poster is Ccing you or whomever on the post
 > so you are receiving it directly from the poster and not from the list.

And the recipient(s) have nodups set in their subscription to that
list, to complete the confusion.  (It's also possible that the MTA or
the MUA is filtering dupes -- the message IDs will be identical -- for
them, and the direct mail just gets there a little faster.)