It seems to me that there was a mistake made when selecting featured image for current week. The last two (deciding) votes have been cast after voting deadline - see current winner's reputation history.
Since voting deadline is the only rule written in large friendly letters, I think it should be honoured when counting votes as the community seems to have agreed.
I think this kind of problem can only occur if the top images are scoring very close, in which case their votes should undergo a closer inspection.
Perhaps the results should be fixed?