My Mavic has had this issue from virtually day one right out of the box. Have done every physical check of hardware & every calibration known including prop balance and vibration check. Nothing worked until I found this solution. Put a Polar Pro ND filter on it the jello disappeared. Not saying it will work for all but when all else failed it worked for me, 12 flights since using filter No Jello.
My Mavic
You Tube Video on the culprit.
My Mavic
You Tube Video on the culprit.