I'll give an example of what I think to be a bug.
Say someone has 1 reputation. I vote up, he now has 6. Someone vote him down, he now has 4. I cancel my upvote, he now has 1. I upvote him again, he now has 6, and not 4. Please confirm if this is indeed a bug.
This is the case, he has 6 reputation even tho he's downvoted once and upvoted once. (and down voted once on another question even! So he should have technically 2 reputation.)