I definitely think it could have been a tip stall. When EDF is first launched, they usually struggle to fly for a little bit and sink before they start really flying. If this model was still sinking after the launch and had its nose pointed up with a little bit of elevator, then it could have easily reached critical AoA, tip stalled, and met terra firma. I think this problem would disappear if you let the model fly for a little longer and build up more speed.