I had a problem with my X1C so I had to to alot of surface tests to figure out where the problem was. Had to post to reddit aswell so that's why I put this model online because people in the reddit thread wanted to check my model/print settings to see what results they got so we could compare and see what was faulty in my printer. So the pictures have a bad top surface, in the end it was the X axis gantry and bambulab send me a new one. So use this model to check your top surfaces if you suspect something is wrong.