Are you saying in motors tab? Flip overs are almost always one of a handful of problems
1. Check FC orientation make sure in setup tab 3D movement in terms of tilt and right side up make sense with what the quad is doing in reality while plugged in.
2. Props or motors are in wrong position, can check motor direction and motor number assignment using motors tab with props off.
3. Once you know motor numbers and direction match then last thing that can cause flips is props on wrong.
For the pwm signal you see are you using rc receiver for input to FC? Have you done any funky resource remapping? If you have air mode on and bench testing can expect some strange runaways to high or low throttle since no control authority on the bench with props off.
FC = Flight controller it's the main board in the center of the quad that takes in receiver input and outputs throttle control signal to the ESCs (electronic speed controller) which in turn controls the flow of power to the motors.