What I expected to happen was just a normal minecraft world graphics
*What actually happened was blocks that were there became invisible and random world chunk images appeared repetitively every where, especially where it shouldn't be. Inconsistent.
Steps to Reproduce:
1. Started world
2. Changed main hand to left
3. left and came back into the world
4. Note: can't seem to reproduce it my second PC.
It may be our old computer, but if you could look into it that would be great.
Turn on VBO's in the video settings, and make sure your graphics card drivers are updated.