My app's (simplified) structure is this:
The problem is with this specific constraint which is between the view and the top of the bottom layout guide.
Select the constraint and edit its "Second Item" property
Here you need to choose bottom
Once you have that, the pink view is not influenced by layout guide anymore. The layout guide seem to acknowledge that the tab bar is hidden only after the root view of the pushed view controller is in the bounds of main screen and this happens only when the animation is finished.
And that is the reason the view hierarchy needs to be laid out again which causes the unwanted animation.