Unwanted Xray Vision

Put the summary of the bug you're having here: Every time I log in to play MC, I always get xray vision and I don't want it. I don't prompt it either. It does this on it's own. There are usually very large plots of ground that I can see through which makes it difficult to traverse without possible harm done to character.

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
Just start the game and the xray vision is there.
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