What is the reason for control valve passing

What could be the probable causes of the control valve passing

It could be because of many reasons

Bench Set is set too low.

The valve Plug is not seated.

Plug or Seat is washed out.

The body is washed out.

The air signal to the Actuator is incorrect.

The bench set is not proper

Calibration not proper

Disc damage

Plug scratch

Dust particulars in the body