Just got the phantom 2 with fpv and DJI Zenmuse H3-3D Gimbal. Oem stock white controler. Drone fly's perfect. Except every flight or other flight all the sudden it will just go down with no controls. Drone goes down straight no crash or wobble. touches the ground maybe bounces and controls come back and goes back up. Sometimes you get the control back before it hit the ground and you can bring it back up. any ideas suggestion? the company the we bought it from say they have never heard of this problem. They said to try the advanced calibration on the computer, which we have never done before assuming the company did it when they set everything up.We do the 360 calibration every time with no error lights. We have flown it about 10 times and really want to take it over water but can't unit the problem is fixed. almost every time or every other time it does it once per flight. Still have to try the advanced calibration. Hoping it will work. Could it be some WiFi signal interference? Does anyone have any suggestion? or experienced the same problem?