Hi.
I found an interesting bug while playing in the brand new pre-release 1.8.

• What i expected to happen was - :
  i changed the Render Distance from 12 to 22 to enjoy a beautiful landscape.

• What actually happened was - :
  the chunks glitched : the game was generating pretty fast the same chunk everywhere while i moved the camera.

I recorded this, you can watch it here : https://www.youtube.com/watch?v=M-OEVkUjNxY

• Ways to reproduce it - :
  _get your Render Distance to 12 or less (the settings were like that for me
  _change it to something bigger, around 20 or more
  (try to reload chunks, it may "work" this way)

When resetting this to 12, the "default state" for me, everything went normal, no more glitches.

I hope this report will help you.