Now, I'm assuming this is because the devs messed with the hitboxes, rather than just a plain bug. .however..
I've had several arrows go Through an enemy using the gothic plate.. Not to mention him spinning with a pike and hitting Sideways on the pike and still getting his stabs.
As you have already lowered archers speed by nearly 30 and their damage lowered as well, why mess with the hitbox on it?