Issue description:

Everything have been working fine for a long time

What happens:

Server keeps crashing as soon the overworld is done loading.

What you expected to happen:

Server to start up normally

Version (make sure you are on the latest version before reporting):

• Minecraft: 1.11.2
• Forge: forge-1.11.2-13.20.1.2421-universal
• Refined Storage: refinedstorage-1.4.20

Does this issue occur on a server? [yes/no]
yes

If a (crash)log is relevant for this issue, link it here:

• https://gist.github.com/FiveEYZ/446a995726813b20f7da318e7115d7f8

[pastebin/gist/etc link here]

• http://paste.ubuntu.com/25178171/ crash start at 17696 (more of them keeps popping up after it!)

weird thing is that i restored a couple of hours old backup and now everything works again