I have the same "[API] cannot add handler to 3 from 3 - dropping" message in my App, but I am working in SwiftUI. It looks like my problem is caused by each view which contains a "NavigationView". Changing the NavigationView to a NavigationStack solves the problem. I do not know the equivalent in UIKit. Hopes this will get someone on the right track.

Same problem on Mac for me, but app does not crash. I keep getting this message while opening any other screen in my app, even the screens without the re-sizing mechanism. I found that any screen with an old-fashioned "NavigationView" has this problem, but the new "NavigationStack" screens do not have this problem. @Apple: should I change my app from NavigationView to NavigationStack now, or can I wait for that in a future release?