I am using item 5, and got the same problem.The problem is at the interface of 2 and 5.
The pins on 2 are too short, or the small copper plates on 5 are too much "digged" in part 5.
I have tried to push up the copper plate, but dont find the solution to do it with a small screw driver. Is it possible to have a drawing that explain how these plates are mounted ?
As a temporary solution, I use some small aluminum plates to improve the contact.