After changing the NoAI tag of Mobs, mobs will suddenly be hurled into the sky very high.

Steps to Reproduce:
1. Make a large-enough lake or find one
2. Put any Mob in the water
3. Run command:

/entitydata @e {NoAI:1}

4. Wait 2-3 seconds
5. Run command:

/entitydata @e {NoAI:0}

Repeat(if not reproduced)