LISTSERV has to calculate the checksum and see if the note is a duplicate
before it distributes it (obviously). At this point it also updates the
checksum file, because the logic becomes quite convoluted afterwards. I
will see what I can do to solve this problem, but for now you should just
repost your note with some comment inserted at the top or ask the
postmaster to remove the checksum in question from the checksum file.
Eric