Chunks start disappearing when 2 people are on a server

Put the summary of the bug you're having here

What I expected to happen was...:
I was expecting chunks to load when there are 2 or more people on a server

What actually happened was...:
Chunks starts disappearing after there is more than 1 person on a server

Steps to Reproduce:
1. Start server
2. One person logs onto the server (Server runs normally)
3. Second person joins server (Chunks start to disappear)