Scrolling back up on list with variable height cells causes jank

[pfives]

Scrolling down is fine. When scrolling back up, if I fling it the scroll seems to be fine but slow drag scrolls cause the list to continually jump back down to where the scroll started. In essence you end up often scrolling up the same image over and over as the whole list jumps back down.

Any one run into this? Know issue? Thanks