Put the summary of the bug you're having here

What I expected to happen was...:
Enter the Nether to derp around
What actually happened was...:
No chunks beyond about 4 around portal load, no "true" block or entity interaction, minecraft crashes soon either by closing or a "Run out of Memory" message.
Steps to Reproduce:
1. Could not reproduce in separate worlds, limited to that specific but ordinary world, constant crashing, fixed only when applied 3rd party position editor to place player in overworld