I have had this exact type of crash. The barometer is not a perfect judge of height. The drone calculates height relative to take off. I don't think 12 feet is that big of a difference in my experience. I fly in the negative all the time. The video shows the vegetation immediately after the failure. I don't get the sense that the drone fell 10+ feet before we saw grass. A Phantom 2 had several inches of clearance to the props, a Mavic has almost none. You may as well have sent it back but if it was damaged, DJI won't refund it. If you got it from a retailer, you may have better luck with them.