Issue Description: If you attach item conduit to an item buffer on two sides. Set one of the item conduits to extract, the other to insert. Then in the item buffer, set the side that has the extracting conduit to push. All of your items in the item buffer will disappear. If the description was unclear let me know and i'll get a photo to explain better.

Note: If this bug occurs in a modpack, please report this to the modpack author. Otherwise, delete this line and add your description here. If you are using an unreleased version of Ender IO (e.g. for 1.8.9), please don't open an issue for features that have not been announced as "finished" or "working".

What happens: Your items disappear from the item buffer.

What you expected to happen: Not all of my items to disappear. Maybe them to go in a circle? I'm not really sure what I expected.

Steps to reproduce:

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Affected Versions (Do not use "latest"):

• EnderIO: 1.7.10-2.3.0.428_beta
• EnderCore: 1.7.10-0.2.0.36_beta
• Minecraft: 1.7.10
• Forge: