[Samba] lists.samba.org's Mail Servers Are A Bit Wonky?

[Sonic]

On Fri, Aug 28, 2015 at 3:09 PM, Jim Seymour <jseymour at jseymour.com> wrote:
>   $ host -t mx samba.org
>     samba.org mail is handled by 10 smtp.samba.org.
>     samba.org mail is handled by 5 ns1.samba.org.

Might be an error, might be some sort of anti-spam set up as well.
Could be one just answers privately. Do note that the mailing list
address is @lists.samba.org whose MX records vary slightly from those
of @samba.org:
=========================================
$ dig +nocl +nocmd +nocomments +nottlid lists.samba.org MX
;lists.samba.org.       IN MX
lists.samba.org.        MX      10 lists.samba.org.
lists.samba.org.        MX      10 ns1.samba.org.
=========================================
$ dig +nocl +nocmd +nocomments +nottlid samba.org MX
;samba.org.             IN MX
samba.org.              MX      10 smtp.samba.org.
samba.org.              MX      5 ns1.samba.org.
=========================================

Both include ns1.samba.org (the one not answering publicly).

Note that lists.samba.org and smtp.samba.org have different IP addresses.
=========================================
$ dig +nocl +nocmd +nocomments +nottlid smtp.samba.org A
;smtp.samba.org.                IN A
smtp.samba.org.         A       144.76.82.148
=========================================
$ dig +nocl +nocmd +nocomments +nottlid lists.samba.org A
;lists.samba.org.       IN A
lists.samba.org.        A       144.76.82.147
=========================================

I've never experienced a problem sending to the list. Also any
properly working mail server should have worked as well. If one MX
server doesn't answer it should try the next one... as long as one is
up the mail should go through.

Chris