[Mailman-Users] Determining why a message is discarded?

[John R. Ackermann N8UR]

I have a user whose postings to one of my lists are being discarded.  By 
all indications, they should go through -- the are from a subscribed 
address, mail isn't being held for bounces, etc.

I've changed all the list settings from "discard" to "reject" yet his 
most recent message still shows up in /var/log/mailman/vette as discarded.

Any clues on what might be causing this, or on how to further dig into 
the problem?  The discarded messages don't seem to leave any suspicious 
traces in the other mailman logs.  (FWIW, I recently upgraded from 2.1.4 
to 2.1.5; the Debian upgrade script reported that everything converted 
over without problems.)

Thanks,

John