After updating to latest software, Imu and compass calibration I flew today over a lake. No wind, water was very calm. Flew about 2 feet over the water. Tried with oa on and oa off, P4 was very erratic. Kept rising about 10 feet and was drifting a little bit as well. When not low over the water, it is rock solid. Wish dji would let us turn off VPS.