What sorts of things are regarded when Purify says "Whitelisted"?

I am getting spam emails coming through as HAM with the following headers:

X-PURIFY-RATING: HAM
X-PURIFY-REASON: Whitelisted (From)-'es'

I have looked through my Whitelist expressions and found nothing that would do this. I assume that if this expression were in my Friends list Purify would say 'es' is a friend

I'm wondering what else might trigger Purify to say "Whitelisted" ? All of these false positives are relating to the From: header.

You've got a regular expression that is matching this I'm afraid.

I couldn't be much help without seeing your whitelist, and I don't recommend posting it here.
You could export, and send it to me.

Should I export just my Whitelist, or also my friends list?

the whitelist is easy (but that makes figuring out the source of the problem hard)