Built a quad frame and it was flying well on the test flights. I then completed a few missions with mission planner. On the last one I came into land flipped from Auto to Loiter to take over and land. I got 3 feet off the ground and it started to drift un-responsively. I then hit the throttle to shoot up over the fence got to about 50 feet and then it pitched to the side and started heading toward the ground without any control at all while losing elevation. Luckily I flipped through the flight modes until Alt hold became responsive before the drone hit the ground. Can someone confirm if this is a firmware issue, Pixhawk issue, or my issue? Really appreciate the help here as I am new to the pixhawk community. Thanks again!