Self-Controling Bug

What I expected to happen was...:
I was only play minecraft as usually normal

What actually happened was...:
The lag that make player control itself

Steps to Reproduce:
1. CPU is should be 100% (That make the game lag)

2. Set render distance to 8 blocks

3. Create a world

4 Press W, A, S, or D (for movement control) for a few second.

5. Release it.