Put the summary of the bug you're having here

What I expected to happen was...:
To load my world and everything be just fine as I left it yesterday. Today is 5/14/14

What actually happened was...:
There was a glitched hole that was all the way down to void. But it was thinking the blocks were there and it was glitching.

Steps to Reproduce: I just loaded a world and it was there and it doesn't happen always just on the occasion. This has happened before in 1.6.4 as well but I was using a mod so I thought it was a bug with the mod but I didn't know it was minecraft.
1. Put a step by step guide on how to trigger the bug here
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