Hmmmm, this doesn't change a lot.
It seems more and more that something is odd respective scaling. The more I see about it in the forums the more I realize what lets Reaper videos look kind of choppy (for scaling) comparing to other video editors outputs.
I had no time to make my announced test in detail but I'm pretty sure this will show that something is elementary wrong with scaling. As I know for now it updates only after view frames. And this can't be right.
Here is another example:
https://forum.cockos.com/showthread.php?t=196263
At the moment zooming is not usable for serious applications. By the way, your along the way released motionblur is so amazing. This alone is such a great addition to the video processor ... unbelievable.
But it can't be the solution to stuck 10 of those presets on top of a slowly zoom. Okay, it could be the solution, but with a lot of silly feelings in the belly.