I've talked to Fred, my boss and local ezmlm/qmail expert.
According to him, assuming the outgoing message ids are not
identical, this is probably caused by the list's .qmail file -- if the
ezmlm line is followed by other lines which can cause temporary
errors, the entire delivery will be retried, resulting in duplicates
going to the list (potentially, a lot of duplicates).
So the .qmail file needs to be reordered, with anything that should
cause a temporary error (ie, a retry) going before the ezmlm
line...and with anything after deliberately not reporting errors at
all -- instead of one of
command
command || exit 111
It should be
command || exit 0
for all commands following the ezmlm line.
--
Joshua Kronengold (mneme@(io.com, labcats.org)) |\ _,,,--,,_ ,)
--^-- "Get your mind right and you can make a stick /,`.-'`' -, ;-;;'
/\\ your wand and the sky your hat and a puddle |,4- ) )-,_ ) /\
/-\\\ your magic..." -- Granny Weatherwax '---''(_/--' (_/-'