I am not sure what the issue is, gimbal or video settings.
I posted on this forum to see if anybody else had the same experience and may have a fix.
I got the same result at 1080p 120f/s, I am not using any filters.
I don't believe it to be a shutter issue, if the drone is not yawing and is still or moving forward all moving objects in the frame move smoothly, i.e. movement from forward motion, moving cars, waving trees, birds that fly through the field of view.
As soon as the craft rotates even slowly the video is rendered as a series of small distinct steps, the closer the object the more obvious the steps. Apart from the jerky pan I am very happy with the Mavic video quality.