I did not produce it on purpose, and only noticed it as I ran past once and my robots took off, so I waited and watched to see what they were going to do.

Placed the setup via blueprints and robots, that's as specific as I can be sadly.

http://puu.sh/yEkpf/9579f84d59.png So my personal robots take steel chests from my inventory, and try to place them where they already are. I've removed the chest and replaced them myself, the bots didn't actually place the chest in the blank space left behind whilst I was removing them either. Wha...