I just came from block testing on the duel server against Aine_of_Rose. We couldn't reproduce the blows passing through blocks after several attempts, but the one weird thing that did happen was that I could block blows which weren't aimed at me: Aine turned facing about 90 degrees to one side so a sideways swing was obviously not going to intersect with me at all. It still got blocked, as if my hitbox were about a metre forward and right of where it should have been. All the blows were taken slowly and carefully, however, so it may not have been a very good reproduction of the typical fight.