Anti-spam re-classifying SPAM

Like many people out there, I also have my mailserver check for spam using SpamAssassin. I have SA configured to add a tag to the subject line of identified SPAM messages and then I have a filter in Outlook to dump all those in the Junk Mail folder.

Since installing ESET Smart Security, I find that the SPAM tag has been removed by the Anti-Spam module and those spam messages are then place in my Inbox. Since I also have all this stuff being forwarded to my phone and I get close to 200 spam messages a day, I was a rather annoyed to find that messages already identifed and tagged as spam are being legitimized by the anti-spam module.

Has anyone else noticed this behavior and is there a work-around? My current work-around is to turn the anti-spam module off since it is not useful to me in the current state.

Wouldn't it have been better to include a config setting to trust messages already marked as spam? (I.e. analyse the mail headers etc.)