ezmlm-idx>=0.313 removes all but the latest ‘Received:’ header from messages sent to the list. This is done since messages, especially sent via sublists, may have so many ‘Received:’ headers that MTAs with primitive “loop detection” erroneously reject them. The subscriber can subscribe, since those messages have fewer such headers, and will receive warning and probe messages, but never see any posts.
To see all headers of a message for diagnostic purposes, mail ‘mainlist-getv.num@mainhost’, where ‘num’ is the message number. All ‘Received:’ headers are stored in the archive copy of the message.
To disable ‘Received:’ header pruning, use the ezmlm-send(1) -r switch.