The last couple of projects I have had a recurring issue. Midway through the cut one of my y axis moves a different amount them the other side. When I measure the distance from the gantry on both sides there is a difference of 3/8 of a inch or more. This has happened 4 or 5 times now. I have reset the wheels, the nut at the end of the threaded rod, checked screws. But is still happening. Any suggestions?