I have been flying My Mavic Pro for over 8 months. The current firmware version is 1.04.04. I am encountering what I call a "wacky gimbel" behavior. The gimbel appears to have lost vertical and horizontal alignment. The drone has never been crashed. I have tried to re-calibrate the gimbel; however, calibration fails; with error message that the device in not on stable surface. I had a brief realignment; when I reset the gimbel in the DJI GO 4 on my iPhone X. Any assistance would be appreciated.