Running WordPress 3.1, Akismet 2.5.3, and NoSpamNX 4.0.2.
My editor called me this yesterday telling me that one of our sites was having an issue, where a few comments were incorrectly flagged as spam. I thought it was because they were running 4.0.1, so I upgraded to 4.0.2. But I got a call this morning, telling me it happened with 5 more comments yesterday on that same site, and even flagging his own two replies!
I tried this as well, and had the same issues. After I deactivated NoSpamNX, the problem immediately went away. Reactivated it, and the problem returned.
I ended up downgrading to version 3.22 for the time being, and that has solved the problem. But I have 60+ heavy traffic sites running 4.0.2, so if there's a problem I want to catch it before it causes a huge problem for us.
Any help you could offer up would be greatly appreciated!