So as I was exploring the end I suddenly saw the world generation is broken. Near 28.5 and 29.5 million blocks out the big end islands were literally cut off.  Look at the attachment for a better description 

Steps to reproduce:
1) go to the end
2) teleport to 28500232 60 0

3) fly north or south till you see a big end island 

The same issue appeared at 29.5 mil blocks, only off with about 20 blocks.

I did not see the issue at 27.5 mil blocks.

Just found it at 26540055 60 0

If both the x coordinate and z coordinate are that high the islands will make a corner like pattern. 

 Here's a more descriptive bug report:

MC-178658