2005 Cadillac STS side mirrors popped

Please advise or reason why when I adjusted my side mirrors it moved on it own with a popping sound

If you are adjusting the mirrors they are not moving on their own, they are moving at your request. The popping sound may be from failing mirror actuator motors.

Does the popping sound occur while you are adjusting the mirrors or after a period of time after you have adjusted the mirrors?