Hello,
I don't know how to describe it exactly. The point is that if you have an animation in your project (manual animation, tracking ..), if you render to a different resolution(while maintaining the aspect ratio) or frame rate(half fps for example) than the project settings, the animation positions have the wrong location or poor timing.
This means in a different resolution(4k project to 2k, or 1080p rendering for example), : Animation / motion tracking has a crop, so they are in the wrong place
At a different frame rate (60fps project to 30fps render, for example): Animation / motion tracking has half the speed.
It's ok? If i am used to other post-production programs that render animations are automatically converted to the final resolution, just like video footages are automatically recalculated (the same way I see it in the preview window that also has a different resolution).
Perhaps you understand me, I apologize for my English :)