mail-filter/spamassassin-botnet gives a false positive for all IPv6 connections. If you use a mail relay that makes connections over IPv6, all incoming mail will be falsely marked as spam. If you run a mail server that is dual stack and sometimes gets connections over IPv6, likely a lot of mail is being marked falsely as spam. A explanation of the issue (and a patch) can be found at http://osdir.com/ml/users-spamassassin/2011-01/msg00110.html Reproducible: Always
Patrick, I don't use this plugin, I didn't test solution but fix is simple. Maybe it would be worth to fix it?