I would also note that it is possible it is the mailing list exploder on
nongnu,org that's doing it - detecting a To/Cc header with an address that's
also on the list, and dropping that address from the list expansion. That
would be (just slightly) less broken than having the receiving MTA drop
a message because it assumes a later one will arrive, and I'd actuually
give a higher probability than the "gmail hid it" hypothesis.
That is possible, but I've personally received duplicate messages from the
mailing list and a local copy, and having nongnu.org delete a message it
thinks is duplicate strikes me as broken as well. Would be interesting
if we could see what happened on the gmail side.
And while I'm commenting on "issues" the "Error: Malformed IPv6 address" from
the Received header from eggs.gnu.org might be because of the (quite) recent
decision that abbreviated IPv6 addresses shouldn't be used (no ::s),
Wait, when was that decided? I looked at RFC 4291 and it's updates and
I didn't see that mentioned.
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