A single account in our Zimbra 7.1.3 server is having ham messages placed in their Junk folder. Example headers from such a message are...

X-Spam-Flag: NO
X-Spam-Score: -2.9
X-Spam-Status: No, score=-2.9 tagged_above=-10 required=4.4
tests=[ALL_TRUSTED=-1, BAYES_00=-1.9] autolearn=ham

and the subjects are NOT prefixed with [SPAM].

As the example above has been autolearned as ham, and the docs indicate that "Zimbra uses a percentage value to determine "spaminess" based on a SpamAssassin score of 20 as 100%. Any message tagged between 33%-75% is considered spam and delivered to the userís junk folder" and our negative score doesn't meet that threshold, I'm further confused as to why this would be placed in Junk.

Other non-SPAM messages to other users with lower SPAM scores (ex: -4.1) are NOT placed in their respective Junk folders.

Can someone enlighten me?