Enemys with the type: "keese" do not hit link if he stands below a dungeon wall

To reproduce in a new quest - make a new "fixed nes" quest, fill a dungeon style room with keese, then stand below the top wall and never get hit
I replaced the top wall with walkable tiles and the keese go higher but not to the new top, I also moved the wall down and link was still safe directly beneath the top wall.

This behavior does NOT happen in the 1st quest that ships with ZC though... so I was going to make a post asking how to fix this problem in my quest, then I thought I should reproduce it in a new quest and that made me suspect it is infact a zc bug. I didn't see it mentioned anywhere else on the forum though. Seems like either the keese collision is too low, or they think they are hitting the top wall too soon.

Anyways here's some relevant info:
tried on both windows 10 / windows xp
using 2.50 build 29 and 2.50.3 RC1