Hello, recently on this mailing list (cyrus-devel@lists.andrew.cmu.edu) there were messages From: Anatoli <m...@anatoli.ws>. For that domain DMARC policy=reject applies. So the MLM is supposed to mungle the From: domain, but it does not do so. In turns the emails from that recepient over the mailing are subject to reject at the final mailboxes.
It is pure accident that I found this out (just seeing replies from Ken to emails which I have not received, more emails in the online archives, which I have not received; generated DMARC failure reports, which were sent nowhere, as the DMARC report has no rua= and ruf= tags). I can offer mailing list hosting at @lists.aegee.org with DMARC mungling for free. RFC 5465 IMAP NOTIFY capable client is Gnome Evolution: https://gitlab.gnome.org/GNOME/evolution-data-server/issues/183#note_730696 Greetings Dilyan