Any pullover vest will ride up or roll up on you if you fall. There is no way around it. I have a LF Cardigan, and friends of mine have had, Ronix, Oneill (guru and checkmate), Billabong, etc.
I don't think there is any way around it, but you can mitigate it by getting the tightest fitting one you can. FYI, they don't float very well. I usually only wear mine when I'm wearing a fullsuit, since the suit itself provides enough extra floaty.