SpamAssassin sending legit emails to spam, despite sender being whitelist

I can not for the life of me figure out why emails from a "white-listed" sender are still getting very high scores from SpamAssassin and not being delivered.

The email headers are:

From orders.usa@theirsite.com Wed Apr 25 10:52:26 2012
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
    www.mysite.com
X-Spam-Level: 
X-Spam-Status: No, score=-**107.9** required=5.0 tests=AWL,BAYES_00,HTML_MESSAGE,
    KHOP_DYNAMIC,MIME_QP_LONG_LINE,**USER_IN_WHITELIST,USER_IN_WHITELIST_TO**
    autolearn=ham version=3.3.1
Received: from webaccess.theirsite.com (webaccess.theirsite.com [81.246.110.67])
    by www.mysite.com (8.14.4/8.12.8) with ESMTP id q3PHqPpR019683
    for <alison@mysite>; Wed, 25 Apr 2012 10:52:26 -0700
X-Envelope-To: <alison@mysite.com>
Received: by webaccess.theirsite.com (Postfix, from userid 1001)
    id DA5E64223F; Wed, 25 Apr 2012 19:52:21 +0200 (CEST)
Received: from beovpzardb1.theirsite.local (65.110-246-81.adsl-static.isp.belgacom.be [81.246.110.65])
    by webaccess.theirsite.com (Postfix) with ESMTP id B1C794218A
    for <alison@mysite.com>; Wed, 25 Apr 2012 19:52:21 +0200 (CEST)
Subject: RE: questions about garbage cans
From: =?utf-8?Q?Orders_USA?= <orders.usa@theirsite.com>
To: =?utf-8?Q?alison=40eefaco=2Ecom?= <alison@mysite.com>
Date: Wed, 25 Apr 2012 19:51:11 +0200
Mime-Version: 1.0
Content-Type: multipart/alternative; 
 boundary="=_fC3CzCFWmN93q8ZWTzGby0LlKwQH2gYGeZlQzD+NmoGVrVuE"
In-Reply-To: <005701cd22e7$e79eb4a0$b6dc1de0$@com>
References: <005701cd22e7$e79eb4a0$b6dc1de0$@com>
X-Priority: 3 (Normal)
X-Mailer: Zarafa 7.0.6-32752
Sender: =?utf-8?Q?S_Danner?= <s.danner@theirsite.com>
Message-Id: 
 <zarafa.4f98398f.1ba8.4a80d64c7fe5d835@beovpzardb1.theirsitea.local>
X-Copyrighted-Material: Please visit http://www.theirsite.com

Any help here is greatly appreciated 🙂

From /var/log/maillog

Apr 25 10:52:26 www sendmail[19683]: q3PHqPpR019683: from=<orders.usa@theirsite.com>, size=15656, class=0, nrcpts=1, msgid=<zarafa.4f98398f.1ba8.4a80d64c7fe5d835@beovpzardb1.theirsite.local>, proto=ESMTP, daemon=MTA, relay=webaccess.theirsite.com [81.246.110.67]
Apr 25 10:52:26 www spamd[8985]: spamd: connection from localhost [127.0.0.1] at port 56915
Apr 25 10:52:26 www spamd[8985]: spamd: setuid to mail succeeded
Apr 25 10:52:27 www spamd[8985]: spamd: processing message <zarafa.4f98398f.1ba8.4a80d64c7fe5d835@beovpzardb1.theirsite.local> for mail:8
Apr 25 10:52:27 www spamd[8985]: spamd: clean message (-107.9/5.0) for mail:8 in 0.7 seconds, 15956 bytes.
Apr 25 10:52:27 www spamd[8985]: spamd: result: . -107 - AWL,BAYES_00,HTML_MESSAGE,KHOP_DYNAMIC,MIME_QP_LONG_LINE,USER_IN_WHITELIST,USER_IN_WHITELIST_TO scantime=0.7,size=15956,user=mail,uid=8,required_score=5.0,rhost=localhost,raddr=127.0.0.1,rport=56915,mid=<zarafa.4f98398f.1ba8.4a80d64c7fe5d835@beovpzardb1.theirsite.local>,bayes=0.000000,autolearn=ham

What Sendmail is doing

Apr 25 10:52:26 www sendmail[19683]: q3PHqPpR019683: from=<orders.usa@theirsite.com>, size=15656, class=0, nrcpts=1, msgid=<zarafa.4f98398f.1ba8.4a80d64c7fe5d835@beovpzardb1.theirsite.local>, proto=ESMTP, daemon=MTA, relay=webaccess.theirsite.com [81.246.110.67]
Apr 25 10:52:27 www sendmail[19855]: q3PHqPpR019683: to="|/etc/mail/jprocess alison@mysite.com", ctladdr=<alison@mysite.com> (8/0), delay=00:00:01, xdelay=00:00:01, mailer=prog, pri=45901, dsn=2.0.0, stat=Sent