email being (possibly) incorrectly tagged. Why?

[Jason S. <ja...@sj...>]

Dear List,

I am using Pyzor on our company's mail gateway server. We are running
postfix, amavisd, SpamAssassin, Razor, and Pyzor. We like all of those
softwares a lot.

I was testing something completely unrelated this afternoon when I sent
a test email to myself from my ISP's email server to my internal
corporate address, examined the headers, and discovered that Pyzor had
tagged my message.

The body of the message was empty & the subject said "test 678".=20

Since this message was from my account at my ISP to my corp' account, I
can not figure out how any one out in the public internet could have
tagged this messages to get Pyzor to tag it. Or am I misunderstanding
something. I thought Pyzor was a completely human activated tagging
system, meaning that someone would have had to have seen the message in
question and reported it as spam. Since this message could not have
possibly ever been seen by any one before, how could it be tagged?

Any tips or advice is most appreciated.

Thanks.

Jason
ICQ : 127795461