The giant dose not have an AI

The giant dose not have an AI when I summoned him in. Also he takes damage from instant damage potions.

What I expected to happen was...:
He goes around like a normal zombie and heal when a instant damage potion hits him.

What actually happened was...:
I summoned him in and he stood there doing nothing. I threw a instant damage and he got hurt.

Steps to Reproduce:
1. Type /summon minecraft:giant
2. Watch what happens.
3. Throw an instant damage potion.

4. Nothing happens.