I'm not really sure if this is a bug. In AH, there's no animation for a shot passing throw the window, or armor, it either pings, or bounces off, I pretty sure that in real life, your shot would have passed all the way through the backside of the turret, in AH, that simulates by bouncing off.
I'm not 100% sure about this theory, but I have never seen a shot passing through any vehicle, so this could be the case.