Issue description:

well the server is crashing randomly when there is any kind of autocrafting going on.

it had happened with 3 different RS systems. all had some kind of autocrafting going on.

What happens:

Server is sometimes crashing if there is any autocrafting going on.

What you expected to happen:

that the server does not crash?

Steps to reproduce:

1. start a autocrafting process
2. wait?
3. server might crash after a while
   ...

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

• Minecraft: 1.10.2
• Forge: 12.18.2.2114
• Refined Storage: 1.2 Beta 5

Does this issue occur on a server? [

Yes

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

here is the latest crash log: http://pastebin.com/GGgmRyHb

there are more crashed but they are the same.

already fixed

See #556