After sliding the x-carriage into the base frame, you note that there should be a 4mm gap between the rod clamp X pieces and the Angular Mount, but don’t specify that it should be tightened. this slides forward in the next few steps if not tightened. Should both sides of the x carriage have that distance?
For me on my printer i have around 3.5mm on both side
and i have 93,5mm between the frame and the rod on both sides too
as describe in manual.