Yes they are not so good are they? I am going to make a guess at this. Some lenses and I include leitz ones in that when assembled are screwed together in sections. Now these screw threads have multistart points and my guess is the lens has been dismantled at some time and re-assembled with the lens in the wrong position and wound onto the wrong thread and the focussing scale/rangefinder coupling is well out of adjustment.. Only a camera repair specialist would be able to tell fer certain