When I place a crafting combinator, set to read, against an assembly machine set to craft the green circuit from Krastorio (either recipe), something odd happens. While a signal is certainly sent, and it looks like a green circuit, it is for some reason considered a different signal from the normal one. This can be simply demonstrated by wiring up the combinator to a chest containing a green circuit, and a power pole for viewing. The result shows two signals, value 1, that look like green circuits, instead of one signal with a value of 2.