[1.9] A Nightmare in Candyworld: The Nightmare has terrible jitters during his semi-circular path

Verification Build: 1.9.0.0 Beta 1

Partner Rank: 4

Summary:
During the first stage of the boss fight with "The Nightmare" (Ghast) in Chapter 4, the ghast is teleported every tick (absolute coordinates) back and forth along a semi-circular path. In this version he is jittering because he is also trying to look at the player. 

Impact:

Annoying and visually unstable stage of boss fight.

Repro Steps:

1. Download A Nightmare in Candyworld from Store
2. Create a world and turn on cheats.
3. Start Chapter 4 by running /setblock 1 15 6 redstone_block
4. Play through the chapter until the Sugar Bones boss fight.
5. "/kill @e[type=zombie_pigman]" to end the Sugar Bones boss fight.
6. Wait for the Nightmare fight to begin.
7. Observe the bug.

Observed Results: 

Jittery motion. Video attached.

Expected Results: 
Smooth motion while the nightmare turns his head to keep looking at you simultaneously moving along the path.

Screenshots/Videos attached: 

Yes