in reply to Re^5: Reputation: -4 (+-0.5 -3.5)
in thread Reputation: -4 (+-0.5 -3.5)

the DB wont store any other info.

It surely stores who cast the votes (to prevent duplicate votes). As such, there are two ways to update reputation as a vote is cast:

RMGir was pointing out the former approach was used; the latter would make the effect of the bug transient.

Actually, the latter would avoid the bug completely.