Chicken glitching through Hoppers

Chickens sometimes starts falling through a bottom layer of Hoppers.

They do teleport back in of course, when there is a solid block under the hopper.

If there is air beneath the hopper, they glitch and as soon they touch the ground they walk away.

I tested other Mobs, but this affects only chickens.

To reproduce this, I lure them with seeds as shown in the attachment