I guess I was one of the people voting after it was called. I was offline almost all week, so I didn't get a chance to show up until today. Just saw the poll, saw it wasn't closed, so I voted without reading any further (didn't want to see what other people voted for beforehand, as to not to let that influence my own choices).
I know some people don't know it, but as Lonemagpie suggested, one can fix the days after which the poll will close automatically. It does help avoid these kind of misunderstandings.