Moved compressor from one outlet to another. Now it trips the breaker. Same circuit. Different outlet. Why?
You said down stream: if this receptacle further away from the panel than the original I would suspect a bad connection in the wiring or this receptacle is loose creating a voltage drop.
With reduced voltage the amperage to start the motor will be higher and that could be why the breaker trips, now and did not in the original location.
Yes your motor can draw 3-5x the rated current but only a high end meter could actually see the real peak value even a small reduction in voltage 1% could increase the current the motor draws creating the occasional tripped breaker.
I would be going back and verifying proper pigtails are snug or wraps around screws are snug (you said 20 amp so there should be no back stabs in use but they are a common source on 15 amp circuits however some contractors use stab blocks instead of wire nuts I have only seen these a few times in my area).