Copied from a comment in #23

http://imgur.com/a/nfmIk
I had 115 torches in the backpack to start out. You notice in the top image, I have a full stack of torches in my inventory. I place down 6 torches and then break them to pick them up. They go back into my inventory and get duplicated. As you can see I still have the original 115 torches in the backpack plus a couple additional duplicated stacks. I am using the basic backpack with the restock upgrade.