Beginning a few days ago, Akismet has been consistently marking every single comment left by a long-time commenter on my site as spam. Every single time this happens I go into the spam queue and mark his comment "not spam" and then activate it from pending.
This has been going on with 5-10 comments a day for the last 4-5 days, and only for this one commenter, who has thousands of approved comments and has not changed his email address, link, name, or IP recently.
To add to the oddness of it all, when I go to the Akismet Stats page on my dashboard, Akismet reports zero "false positives" for the time period in question.
Anybody have any idea why Akismet would be picking on one of my users and then lying to me about it?
Also, is there a commenter spam whitelist plugin out there that actually works? I tried this one but it had no effect whatsoever.