Seeing identical behavior. One caveat is my current code is using the back-ported Swift concurrency on iOS 14. The app works fine in simulator and device with Xcode on iOS 14, but crashes on launch with TestFlight build. The TestFlight build works on iOS 15. Haven't tried using older code, but based on what we're both seeing, I think this is an Apple/TestFlight issue they need to fix.

Yes -- use the .popoverTip modifier on the "+" button in your ToolBarItem directly. .popoverTip takes a tip: parameter that will be the Tip struct you've already defined. It also takes an arrowEdge.

It looks like the problem was your "Label" in the button. If you just use an Image as your button content, the tip will work: import SwiftUI import TipKit struct ContentView: View { @State var isSetting = false var body: some View { NavigationStack { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") Text("isSetting: \(isSetting.description)") } .padding() .navigationTitle("Hello World") .toolbar { ToolbarItem(placement: .topBarLeading) { Button(action: { isSetting = true} ){ Image(systemName: "gear") } .popoverTip(TestTip()) } } } } } struct TestTip: Tip { var title: Text { Text("This is only a test") } } #Preview { ContentView() }

App was rejected yesterday for this bug — what’s up Apple?

This same error message occurs in a pure SwiftUI view/project in iOS 26 for a Menu when the view is complex: Adding '_UIReparentingView' as a subview of UIHostingController.view is not supported and may result in a broken view hierarchy. Add your view above UIHostingController.view in a common superview or insert it into your SwiftUI content in a UIViewRepresentable instead. Visual redraw glitch of the menu button is also evident when the menu options are dismissed.