Ive had incidents of this the last few times out.
I think they are VRS stalls, induced, perhaps, by a weak left/front motor.
Yesterday the left front wouldnt start up with the others, or had a hard time starting up. I dindt feel any more resistance than in the others, and strangely, no more heat after flight than the others.
In any case, I had /2/ VRS encounters yesterday, from about the height you mention. On the first one, I crammed the throttle up, the bird bounced and kept flying.
On the second one, it bounced and... took the camera/gimbal halfway off, flipped over on its back and twitched.
I put it all back together last night, and blew out the motors, paying extra attention to the port-front. Now they all start up strong. I think I cured the port-front, and hopefully the ease at which Ive been getting into VRS lately.
The flight videos of the bounces dont show me doing anything radical, except maybe a /little/ too agressive on the throttle-down. In the past, the phantom would tell me when I was about to 'ring' as it would start to wobble. I could react to that. In these VRSs, I was already slow and stable, inch forward and down, and bang. straight to the ground I went.
I hope it was the motor had some junk in it. I hope the easy VRS is a thing of the past.