.....In this treat the body was vented to work against parachuting! Not to do that.
You will have these effect if the body can caught the air effective and give the car a "pull up" like a parafoil.
I have also these kid of effect with my 1:10 Patron with them highly liftet body. If I had mounted the old body much deeper, these effect was not.
Anyway, if you like parachuting, then it is better to buy such thing!