I'm mixing slow motion, crop and full then rendering it to 4k60fps. Here's the problem: When I do a slow mo of my 60fps source down to 1/2 speed, and then crop and scroll, what happens is that the background smoothly scrolls by at 60fps, but then the action in the figure seems to jump back and forth, it looks as if it was doing smart resampling, but it's an effect of rendering 30 fps 1/2 speed action into 60fps. I still need everything in 60fps because most of it is in 60fps. The only solution I have found is if I take every slow motion clip, render it down to 30fps, then re-insert it into the project. Then the back and forth motion is gone. I have a really old version of vegas pro, but went ahead and got the latest version 21 (as a demo to see if I could buy this and fix my problems) just to see if that problem was fixed but it's still there.

It's a lot of extra work to render down every slow motion cropped action shot to 30fps and then re-upload the clip back into the project. Is there some button, or switch something to get rid of that "looks like smart resampling is turned on" look?