I have to agree with the CG as being the problem. I flew my H9 Edge the first time this past weekend with almost identical symptoms. What was also obvious was the tail seemed to be dragging while in level flight. Even though I had the CG set at the middle of the recommended range, I went ahead and moved the 1600mah battery pack forward about 6 inches. When I flew it again it was a different plane. Much more managable and a whole lot easier to land.