Zombie can't reach you if you are 1 block high in creative mode

Hi,
I juste want to report a simply bug in the snapshot.
So:
-I make a zombie spawn in a hole
-Then I hit him (in creative mode)
-Get one block higher than him
The bug is he can't reache me and always try to jump.
I hope it will be usefull
Frank Barber
(Ps: sorry for spelling im french)