There is a really small collision between the screw that holds the wheel for the x axis and the screw that is used in the middle to connect the large O/Frame with the right support structure.
You get rid of the problem when you remove the washer at least on one of these screws. This gives you the reuired 0.5mm clearance. It may also work if the belt is a bit longer and the wheel is more tightened to the right. At least a point zuo should check to get nice surfaces.
