Thanks you two for replying. I'm not sure IMU is the reason since for my Mavic : the drift doesn't appear every flight (most flights but not all), the camera is also drifting slowly to a side and sometimes stops at an angle (not facing straight ahead). On top of that I've had other errors such as gimbal reset mid flight, wheel error, compass error, huge drift when braking... it's really frustrating and it makes it really hard to trust the Mavic. I'm now afraid to fly it above houses, water or anything that could cause damage to my mavic or others. It's a shame, I didn't have any issue with my previous Spark, other than a short range. I've also looked on forums for HOURS and many people have the same problems I just described on their mavics but no one has a fix, just to send it back.