The next place to look is the full email headers 

Here's an example (listname editted to foil the mail-loop detector) of your very message to the list (six mail processes were involved PLUS one approval by the moderator).  Assuming correct time stamps (for those messages that seem to be delayed vs. unimpeded ones), analyses of the delays may begin.

Received: from tr11n05.aset.psu.edu (r02n08-fddi.cac.psu.edu [146.186.157.8])
	by f07n01.cac.psu.edu (8.9.3p2.1/8.9.3) with ESMTP id NAA106052;
	Wed, 12 Apr 2006 13:07:45 -0400
Received: from f05n16.cac.psu.edu (f05s16.cac.psu.edu [128.118.141.59])
	by tr11n05.aset.psu.edu (8.13.6/8.13.2) with ESMTP id k3CH7cH71937446;
	Wed, 12 Apr 2006 13:07:38 -0400
Received: from f05n16 (f05s16.cac.psu.edu [128.118.141.59])
	by f05n16.cac.psu.edu (8.12.11/8.12.11) with ESMTP id k3CGl6W4266484;
	Wed, 12 Apr 2006 13:07:37 -0400
Received: by PEACH.EASE.LSOFT.COM (LISTSERV-TCP/IP release 14.5) with spool id
          105019851 for [log in to unmask]; Wed, 12 Apr 2006
          13:07:09 -0400
Approved-By: [log in to unmask]
Received: from 216.219.253.186 by WALNUT.EASE.LSOFT.COM (SMTPL release 1.0m)
          with TCP; Wed, 12 Apr 2006 12:53:23 -0500
Received: from [66.64.34.114] ([66.64.34.114]:61710 "EHLO COMMUNICATIONS") by
          ams011.ftl.affinity.com with ESMTP id S520430AbWDLQxW (ORCPT
          <rfc822;[log in to unmask]>); Wed, 12 Apr 2006 12:53:22
          -0400
MIME-Version: 1.0
X-Mailer: Microsoft Office Outlook 11
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670
Thread-Index: AcZeUS45rk325FGRTiCcqiZwh0nHgQ==
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Message-ID:  <[log in to unmask]>
Date:         Wed, 12 Apr 2006 11:50:19 -0500
Reply-To: "LISTSERV site administrators' forum"
              <[log in to unmask]>
Sender: "LISTSERV site administrators' forum" <[log in to unmask]>
From: Sheila Fredrickson <[log in to unmask]>
Subject: Strange mail behavior
To: [log in to unmask]
Precedence: list
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