Steps to Reproduce:
To reproduce the bug, simply have a ghast attack you and notice when it fires it's fireball.

Expected Results:
The expected behaviour is when it tries firing, for it to expand, like a slime jumping or a creeper exploding, and then return back just when releasing the fireball. This behaviour can be observed in v1.2.0 Alpha.

Observed Results:
The observed behviour is it being instead completly static, no squish.

Context:
Since version v1.2.0 of Java Edition Alpha, ghasts would slightly expand before releasing their fireball. This didn't work properly in multiplayer. After the change that made all worlds technically servers, it also has stopped working in singleplayer.