Having issue with the TR-18A Stack Decoupler. Not sure about the other stack Decouplers. It is connecting stuff to the piece that is below the decoupler and not the decoupler. You have to disconnect and reconnect the decoupler and it might work and connect to the decoupler. Very difficult at times to get it right. System: 8.1 Windows 64, Steam, KSP Version 1.0.4.861, 1 Mod (The Asteroid Day Mod) Just wanted to let you know this game is great. I love hearing my 11 year old talking about his rockets and enjoying something that is science related.