It gets squirrely because its actually all wrong for high speeds. V drives don't tend to work well with pad bottoms, and the strakes go all the way to the transom. Neither work well with added lift from a prop. The faster you go, the more power you put to it, the more the ass lifts.
Plus like you said, if and when the boat falls off the pad, it will turn into a chine walker, but with the plates only in the center, its pretty difficult to get the hull to stay on the pad.