Crop Tool Behavior

My crop tool works fine for toy cars, but NOT for my coins.  I go back and forth between the 2 just to see the crop tool reaction--NO CHANGE.  Works fine to crop hot wheels, but not at all for my half-dollars.  Now probably tomorrow morning all the coin crops will just "up and appear" as cropped, but not when you need it.  No immediacy to it at all.  A very undependable apparatus at the moment...but the performance "comes and goes".  Just never know when, or IF it will crop as needed.  I might add, when it works, it's GREAT!!