It makes me think of the little war that went on a few weeks ago (or maybe it's still going on? I haven't paid much attention) where numerous Haejin posts were downvoted on the last day. Uncertain if any of that was happening in the last 12hrs or not.
I understand that the initial 12hr window idea was an effort to allow correction of 'unjustified rewards', but this seems to make 'justice' (in whichever direction), more difficult to achieve. Seems to be another classic example of punishing 98% of people that aren't abusing things in response to the 2% that are (or whatever the percentage numbers may actually be).