If the headset has been replaced as the op stated earlier, the extra washer/spacer may have been installed because the stack height on the replacement headset was smaller. If this is the case, the only two options I’m aware of to keep the top nut from bottoming out before it tightens against the cone, is either washer/spacers or cutting the steerer tube. I usually add washers because it’s a lot easier than cutting the steerer tube. I believe this isn’t going to be resolved without taking it apart and inspecting to see exactly what the problem is.