Issue Description:

I was using pistons on server when randomly i have disconected from it. So i tried to reconect, but nothing happen. I tried to reproduce with only Biomes O' Plenty and it seems that picking dropped sticky piston crashes game in Singleplayer and in Multiplayer keep disconnecting. I also tried only with forge but there wasn't any crash.

Steps to reproduce:

1. Take sticky piston
2. Drop sticky piston on grouns
3. Take sticky piston from ground

Additional Information:

• fml-client-latest.log or fml-server-latest.log:
  http://pastebin.com/beSNu9xk
• Screenshots:

Affected Versions (Exact numbers, do not use "latest"):

• Biomes O' Plenty: 6.0.0.2125
• Minecraft: 1.11
• Forge: 1.11 2180

This is probably my fault when fixing the BoP achievements in version 6.0.0.2113. Will look into fixing it later :)