Sam Sartor
Comments
This is a culling/normals problem.
This is to be expected and is normal and unavoidable. The world generation was changed in 1.7 so any chunks from before 1.7 will not line up with chunks from 1.7 or later. This is not a bug, simply the new world gen disagreeing with the old.
Some demonstrations similar bugs:
http://www.youtube.com/watch?v=g5hZtUlrlmo
Please fix this, it has made redstone contraptions and logic difficult.
May or may not be intentional, this certainly seems strange however.