Problem with alert in iOS4.5

2021-05-08 18:21:34.680280+0900 SampleProject12.5[2534:139985] [Presentation] Attempt to present <SwiftUI.PlatformAlertController: 0x7ff27200ce00> on <_TtGC7SwiftUI41StyleContextSplitViewNavigationControllerVS14NoStyleContext: 0x7ff26f825000> (from <_TtGC7SwiftUIP13$7fff5695965428DestinationHostingControllerVS7AnyView: 0x7ff271c06180>) whose view is not in the window hierarchy.

Code Block 
import SwiftUI
struct ContentView: View {
  var body: some View {
    NavigationView {
      List {
        NavigationLink(destination: NextView()) {
          Text("Next View")
        }
      }
    }
  }
}
struct NextView: View {
  @State private var showingAlert = false
   
  var body: some View {
    Button("Show Alert") {
      showingAlert = true
    }
    .alert(isPresented: $showingAlert) {
      Alert(title: Text("Alert!"))
    }
    .onAppear {
      showingAlert = true
    }
  }
}