The way you described it, it does sound like a hall sensor issue. Are you able to attach the sensor to an oscilloscope to see if it is just the sensor before you replace the entire board? Can you take a look at the filament cutters and see if they are misaligned/worn down? I would also re-install firmware to see if there was some error during the flash that caused the sensor to not be programmed properly. Worse case is that it could be an electrical problem, or maybe you have a giant magnet on the right side of your printer 
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Best of luck and let us know what the issue ends up being!