I'm playing in Survival.

How do you describe the bug: Zombies, when hit by punching from a player, it will be knocked back a very short distance, and then it crawls or slowly tiptoes towards the player. After a second or two, zombies would then walk towards you normally.

How to reproduce it:

1. Create a survival world.
2. Wait until night time, or use "/time set 14000"
3. Find a zombie, any type will do.
4. Use your fist to punch the Zombie.
5. Keep noticing the walking behavior after every knockback from your fist.

Any mobs have this problem? No, skeletons do not have this problem, so far. I have not tested this on Spiders, because I get killed easily without getting enough time to study the behavior.