Crash going from Nether to portal to new location in 1.7.2

I went to the Nether, built a portal a bit of distance away, lit it, and it crashed when I tried to go through it.

What I expected to happen was to appear in Normal land at a new location

What actually happened was it crashed during chunk generation

Steps to Reproduce:

1. Go to Nether
2. Build a portal at the same level, a bit above sea level
3. Light it and go through.