[Mailman-Users] mail from one domain (moderators') posts do not show up in pending requests

[KEY5]

Hello,
in my list every user is moderated. None can post. Not even owners and
moderators.

If I send an mail from an address (which is also owner and moderator) it
does'nt show up in the pending requests (it'ts been working like that for
years).

If I send an email from a subscriber/non subscriber email address, it is
shown, and can easily be forwarded to the list.

The not working mail comes from another server on the internet, and arrives
with no problem at my server, (running CentOs+cPanel)
and it is forwarded to mailman. But after that, it disappears. (no
occurrencies with grep domain -r *,  in none of the log/any files in
mailman directory)
I thin the problem is the incoming @domain. Since I encounter the same
problem from another.user at nonworkingdomain.com

Exim log shows:

2013-05-09 17:36:47 SMTP connection from ****.****.**
[***.***.***.***]:28571 closed by QUIT
2013-05-09 17:36:47 1UaStj-0002Or-DO => listname <listname at example.com>
R=mailman_virtual_router T=mailman_virtual_transport
2013-05-09 17:36:47 1UaStj-0002Or-DO Completed


Any hint on where to look for?
Thanks.