I have the same type of dials on my G0602 lathe. The cross feed dial was slipping like your dials. As I recall, the problem was insufficient axial clearance of the dial. I reduced the the thickness of the dial and haven't had a problem since.
You may be able to accomplish the same by adding a thin shim washer between the thrust washer and the crank. It shouldn't take much, only a few thousandths will probably create the necessary clearance. An aluminum can should work. If you sandwich the aluminum between two pieces of scrap, you can drill or use an end mill to make the inner hole. Trim the outside diameter with scissors.