Giants always have no AI

I know there not an important mob, but giants seem to be bugged. In the past, a giant would attack you on site, just like any other hostile mob. They also acted like a mob, randomly walking around and looking around. Now they stand completely still, and never move. They never become hostile, or even look around.

What I expected to happen was...:
Giants to act like a normal mob by attacking me and moving around.

What actually happened was...:
The giant seemed paused in time. I didn't summon it with noAI either.

Steps to Reproduce:
1. Summon a giant, it wont move around at all or even look around.