This happens when someone joins the server in the certain chunk with the item http://hastebin.com/duhanuyitu.vhdl

MC:1.10.2
Forge:12.18.1.2014
Calculator:3.0.6
Sonar-Core:3.0.5

I'm the "someone", and just to elaborate: I placed the flawless greenhouse block down and it crashed the server. The server crashes again if I rejoin.

Same as #140

Just posted the fix :)