Views inside split view resize in real time only when window has full size content view

I noticed that when a window has full size content view, the views inside a scroll view are resized smoothly when adding a new split view item (i.e. in real time while the animation is running), but when the window has not full size content view, only the split view divider animates to its new position, while right from the beginning of the animation the views are instantly drawn as if the animation had already finished.

Is there a setting that allows me to turn these smooth animations on even if I don't use a full size content view?

Here is a sample project and steps to reproduce the issue: https://www.icloud.com/iclouddrive/0zKg8hqwLpV682-6LuxeykZLw#problem2

1. Run the project.

2. Press Cmd-L to add a view to the right of the split view. The text view will resize smoothly.

3. Now deactivate the full size content view for the window in the storyboard and relaunch the project.

4. Press Cmd-L. The text view will resize instantly at the start of the animation, and only the split view separator moves smoothly to its final position.