Constraint doesn't update

Hello

I have a viewController (A) in which I have a view that contains another viewController (B) that's in a NavigationController. That view has an uninstalled height constraint in the xib.

In the code, I set the preferredContentSize of B, and then, in A, I set this function :

Code Block    
override func preferredContentSizeDidChange(forChildContentContainer container: UIContentContainer) {
super.preferredContentSizeDidChange(forChildContentContainer: container)
customActionViewContainerHeightConstraint.isActive = true
customActionViewContainerHeightConstraint.constant = container.preferredContentSize.height
}



In iOS 13, B appears in A.
In iOS 14, however, B is a no show.
Constraint doesn't update
 
 
Q