I created a superflat world, and 11 by 1 chunks from a default world loaded into it.
I think this was just a one off because I tried it again and it didn't do it, just notifying mojang of this. 7862096914888582380 is the seed but recreating the world doesn't load the same as this.
Environment
Windows 7
Duplicate of MC-315, please use the search function to see if your bug has already been submitted. Currently over 57% of tickets are being closed as duplicate.