The Polysher was developed to ensure high detail is maintained this means print defects such as layer shifting or under extrusion will still be visible once the model is polished. After polishing the shadows and glossy surface can make these defects more noticeable. To solve this problem try printing at a slower speed to reduce vibrations, experiment with your retraction settings and try changing the nozzle printing temperature. Alternatively make sure your printer is calibrated correctly.