This appears to be a problem that's happening when your Mavic transitions from hover to forward flight. I don't know if you are running anything other than standard DJI Prop's on the Mavic, but if you are, that could explain this.
This problem has a high probability of being due to a GAIN setting being out. When a Mavic is put into a hover, there are a set of sensors that operate to drive the motors so that it will hold its position (in wind etc.) and be the camera platform we all know & love. The sensors operate using a feedback mechanism i.e. when the Mavic e.g. rolls right, the motor controllers tip it back left at the same force/rate to compensate for the movement (the sum being zero movement). If this feedback mechanism is even slightly out, it can cause; a) an almost imperceptible 'tremble' in the airframe when the drone is hovering, and/or b) a 'tremble' when the drone moves from the hover into a flight path in any 3D direction. The 'tremble' is at a high frequency, and is almost impossible to see - but - will set up a sympathetic 'wobble' in the gimbal mechanism - since it's just hanging there on rubber bands. In case a) the GAIN settings are overcompensating for the drift, and in case b) the GAIN settings are 'fighting' the Mavic when it wants to get out of the stable hover.
The way around this is to adjust the GAIN of the feedback circuits, which can be done in Go4 ... This is a setting that requires trial and error, but as long as you note the initial settings, it's easy to put back to how it was if nothing changes - or it gets worse due to the adjustment.
This is a very good video (long but meticulous), explaining how this all works and what to adjust. Give this a go and I think you'll get rid of the wobble ...