Using .insetGrouped listStyle for List in SwiftUI on iOS14.4 caused a data problem

The code can be downloaded in a tutorial from Apple, the link is here: https://developer.apple.com/tutorials/app-dev-training/persisting-data

Problem code:

struct ScrumsView: View {
    @Binding var scrums: [DailyScrum]
    @Environment(\.scenePhase) private var scenePhase
    @State private var isPresented = false
    @State private var newScrumData = DailyScrum.Data()
    let saveAction: () -> Void
    var body: some View {
        List {
            ForEach(scrums) { scrum in
                NavigationLink(destination: DetailView(scrum: binding(for: scrum))) {
                    CardView(scrum: scrum)
                }
                .listRowBackground(scrum.color)
            }
        }
        // Problem here
        .listStyle(.insetGrouped)
        .navigationTitle("Daily Scrums")
...

On iOS 14.4, I tried to set listStyle to any other style except .sidebar or .automatic, when I go to MeetingView and back to DetailView, the History section hasn't been updated. But if I use these code on iOS 15, there is no problem.

I found that if I use these style, when I pop back to DetailView, the onDisappear closure in MeetingView would be executed, but the "History" section's ForEach function in DetailView wouldn't be executed.

Thanks for anyone who could help me to figiure out my problem.