Sorry to hear about your kite

Any kite that is depowered to the max and/or in gusty conditions can be made unstable by wind hitting it at a downward angle, and it will drop out of the sky. Leading edge pressure has nothing to do with this kind of crash, and there is little you can do about it apart from selecting a smaller kite so that it is not always at the top of the depower range.
That being said, you might not have closed the valves properly and/or developed a leak, and then the kite seems to fly normally until it gets in to some gusty air and/or you load/unload the lines and the kite then looks like it is trying to turn itself in to a taco.
Either way, once a kite spins up or luff-bangs through the power zone you always run serious risk of doing damage to the kite.
How was the leading edge pressure after you got back to the beach?