This happened in versions past 1.9+

I do the /summon command. When i try to use the NBT tag

{NoAI:True}

, it won't work on The Wither. Ex: When i do /summon WitherBoss ~ ~ ~

{NoAI:True}

it still has AI, I'm not sure if this is a bug, but the Enderman will still teleport around with no AI.