OK I am going to try to go into the Spam folder periodically and approve comments that the plug-in erroneously marked as Spam. Apparently, this will help it learn over time which ones to allow and which to divert.
So that means some of you will see duplicate comments, because you resubmitted under a different email address etc. I think the best way to handle this going forward is either of the two following approaches:
(A) You use a single preferred email address. If your comment disappears, then email me and I’ll go approve it. Hopefully the plug-in will soon learn your email address is OK. But this means you have to have patience, while you wait for me to dig up your comment.
(B) When a comment disappears, you use a different email address or some other trick, in order to get instant gratification. But then don’t email me about it, because if I dig up your original you will then have the same comment multiple times.