Order of operations - SPAM and filtering

[SpEnTBoY]

I'm just wondering, when an account recieves spam does it put it in the junk folder typically leaving the user to determine wether or not the claim is valid? This is the way I understood it but then I noticed I was getting some spam messages into one of my folders (one that I have for Zimbra emails) and the criteria for sorting messages to that folder didn't match the spam mesages. I'm basically trying to figure out how they got sorted into a main folder after being marked as SPAM

Here is part of a header:

-Virus-Scanned: amavisd-new at 
X-Amavis-Alert: BAD HEADER, Non-encoded 8-bit data (char E1 hex): Subject: Un
	bono m\341gico en tu prim...
X-Spam-Flag: YES
X-Spam-Score: 11.981
X-Spam-Level: ***********
X-Spam-Status: Yes, score=11.981 tagged_above=-10 required=6.6
	tests=[BAYES_99=3.5, HELO_DYNAMIC_IPADDR=4.2, HTML_MESSAGE=0.001,
	MIME_HTML_ONLY=0.001, SUBJ_ILLEGAL_CHARS=4.279]

This was in my "Zimbra" folder which I send mail to on two criteria:

1. From contains forums@zimbra.com
2. Subject contains a specific FE/Bug I'm following

None of these match up in the headers though. ANyone have any ideas why it might sort these to another folder other than "junk" after being tagged as spam?

Thanks!