No, the pixhawk is not defective. But you do need to follow some instructions in order to get it working.
First update to ArduCopter 4.5.1 firmware version. Then install https://github.com/ArduPilot/MethodicConfigurator/actions/runs/8603225557/artifacts/1394874278 and follow How to methodically tune (almost) any multicopter using ArduCopter 4.4.x