Selection bias, perhaps. Sure, there will be a small amount of miscalibrated machines. And a smaller amount will happen to be miscalibrated to select the wron

Selection bias, perhaps. Sure, there will be a small amount of miscalibrated machines. And a smaller amount will happen to be miscalibrated to select the wrong candidate. But you'll only ever hear about those latter cases. The others will be caught and corrected without internet vitriol.