I've been working on a custom server for some friends and there was a crash with a description of Ticking Block Entity. I saw issue #481 with a similar situation, but the crash reports are different.

http://pastebin.com/mqif3UZq

Modlist:
https://docs.google.com/spreadsheets/d/1lonFgKdmLrsNnNzGt9ROlvgwGkVfYCBjpCfr49qW6W4/edit?usp=sharing

Update and it should be fixed.