If application in app delegate (application:didFinishLaunchingWithOptions:) subscribes to UIKeyboardDidChangeFrameNotification.
[NSNotificationCenter.defaultCenter addObserver:self selector:@selector(_kbFrameChanged:) name:UIKeyboardDidChangeFrameNotification object:nil];In _kbFrameChanged there is no way to detect for what window (UIWindowScene) coordinates UIKeyboardFrameEndUserInfoKey frame is.
So there is no way to proper calculate screen coordinates for keyboard.
Note: This is only occurs when app has 2 or more UIWindowScenes on the screen.
Posible solution: Add UIScreenKeyboardFrameEndUserInfoKey
We suspect that TrackingLayoutGuide for keyboard also uses UIKeyboardDidChangeFrameNotification and it is also affected by this issue.
On following screenshot is example of this app. 2 and 3 windows are separate window scenes. Red view is constrained with UIKeyboardLayoutGuide.
[[_kbTrackerView.leadingAnchor constraintEqualToAnchor:self.view.keyboardLayoutGuide.leadingAnchor] setActive:YES];
[[_kbTrackerView.widthAnchor constraintEqualToAnchor: self.view.keyboardLayoutGuide.widthAnchor] setActive:YES];
[[_kbTrackerView.heightAnchor constraintEqualToAnchor: self.view.keyboardLayoutGuide.heightAnchor] setActive:YES];
[[_kbTrackerView.bottomAnchor constraintEqualToAnchor:self.view.keyboardLayoutGuide.bottomAnchor] setActive:YES];
self.view.keyboardLayoutGuide.followsUndockedKeyboard = YES;And layout system also confuses between windows and apply wrong constrains to _kbTrackerView (red view).