Ok folks. This is where I could really use some help from experience or knowledge. I have a phantom 4 pro. Today went for a quick flight in the back yard. Hovered for a while testing the gps. Had 11 sats, flew forward about 20 feet (no obstruction from sky or gps) when I let go of the stick, the drone lost all power and fell straight out of the sky, breaking the right leg off and cracked the glass on the uv filter. Admittedly, it was an aftermarket battery. But I’ve flown it many times on that battery. Thank God it was only 15 feet altitude. Even after t crashed, it turned right back on (of course I didn’t fly it again, but I wanted to test the camera, props, etc.). Is there something I should be looking for, that would have caused this?