We continue to see an excessive number of email messages that seem to bypass spam filtering. This is not new  to the current version of SM (17.x) but an issue we've never solved, even after opening tickets and tweaking the filters. Without re-hashing old troubleshooting steps (that didn't work), I'm wondering if anyone can answer a simple question:

Why would SM not add weight to a message that clearly is on a blacklist used in the filters? Simple example: SORBS -  Aggregate is in use, assigning a  weight of "4". Some messages which SORBS identifies as spam are weighted by SM's spam filters, some are not.  For those getting through the spam filter and not weighted I'm manually checking the IP's on MX Toolbox, finding they should have been weighted.

To be clear, I'm not expecting 100% accuracy. But messages sent by IPs clearly on multiple blacklists that slip through repeatedly are troublesome and annoying to clients.

It just seems to be incredibly inconsistent. Am I the only one finding SM's spam filters inconsistent ?

Thanks for any clarification to this process!

P.S. - better documentation of how SM 17 spam filters work would be a great asset and improvement.