I would double check the scale resolutions. See section B5 of the manual.
Switch on the DRO, after switching on with the software version no. "VER. X - X" in the message window, press "ent" key to enter the parameter SETUP function.
Go to the RESOLU screen and check the display resolution in MM. if that doesn't work you can do a DRO reset through the menu and reprogram the DRO.