Mobs can STILL be hit through corners

(At least when water is pushing the mob) mobs can be hit through corners.
In the screenshot you can see me hitting a creeper through a corner. The white particle can be seen (of hitting a mob)
I was able to reproduce this in 16w44a with 2 skeletons, although it happens very rarely. So rarely that I didn't manage to get a screenshot, but I'll add a screenshot if I manage to get one.