Sometimes after a flight, i land and put the motors in idle after a shutdown. Then i notice that after a minute or so the Phantoms motors starts spinning faster and faster from the idle speed, until it tryes to take off and tips over. I can counteract it by taking the throttle all the way down. But if i leave the trotlle again in the middel it goes faster, again. This never happens before a flight, only after. Any idea to what is causing this issue? All firmware updated. IMU cal before every flight. Phantom Vision.