This works for me...         if !DataController.isUITesting {             _container.viewContext.undoManager = nil             _container.viewContext.shouldDeleteInaccessibleFaults = true             do {                 try _container.viewContext.setQueryGenerationFrom(.current)             } catch {                 fatalError("###\(#function): Failed to pin viewContext to the current generation:\(error)")             }         }

I'm not 100% sure that my issue was related to the assert warning. However I can see a number of similarities in what some people have reported here. For me, this issues caused a done button on my navigation bar to freeze. My app while running in debug in the simulator with Xcode 14.3 / iOS 16.4 worked fine. If I kill my app and run it without debug on the simulator the freeze would occur. Also occurs on an real device. This is what caused my issue.. [[UINavigationBar appearance] setTitleTextAttributes: [NSDictionary dictionaryWithObjectsAndKeys: [UIFont fontWithName: APP_FONT size: [SharedCommon setAppFontSizeNavigationTitle]], NSFontAttributeName, nil]]; I fixed it with this... if (@available(iOS 15.0, *)) { UIBarButtonItemAppearance *bbItemAppearance = [[UIBarButtonItemAppearance alloc] init]; bbItemAppearance.normal.titleTextAttributes = [NSDictionary dictionaryWithObjectsAndKeys: [UIFont fontWithName: APP_FONT size: [SharedCommon setAppFontSizeNavigationButton]], NSFontAttributeName, nil]; UINavigationBarAppearance *navBarAppearance = [[UINavigationBarAppearance alloc] init]; // .... other appear here navBarAppearance.buttonAppearance = bbItemAppearance; [UINavigationBar appearance].standardAppearance = navBarAppearance; [UINavigationBar appearance].scrollEdgeAppearance = navBarAppearance; } else { [[UIBarButtonItem appearance] setTitleTextAttributes: [NSDictionary dictionaryWithObjectsAndKeys: [UIFont fontWithName: APP_FONT size: [SharedCommon setAppFontSizeNavigationButton]], NSFontAttributeName, nil] forState: UIControlStateNormal]; } Hope this helps someone... Jules.