Although my site is 3.3.1 I was getting these false positives with 3.2.1 too. I don't have this problem, but two of my editors are getting locked out. My editor just got blocked after one try.
I think it might be a conflict between her browser and the plugin. I use Chrome and I don't have problems with it.
Is there anything I can have them try to resolve this issue? I love the plugin otherwise.