NavigationView issue with "Form" Picker inside NavigationLink child

I have a trouble trying to put my Picker inside NavigationLink child struct. MyProblem As you see after some transition (Main Page -> Testing Page -> Picker) and choosing any pickers desire option it navigate me back to Testing Page, but Picker itself stay grey. I know that it can be solved by adding NavigationView{} inside NavigationLink child, but it causes another problem, because i already have NavigationView{} in the top-level ancestor. AnotherProblem_1 AnotherProblem_2

Code:

import SwiftUI


struct ContentView: View {
    var body: some View {
        NavigationView {
            List{
            NavigationLink(destination: page2()) {
                Text("Food input")
            }
            NavigationLink(destination: page3()) {
                Text("Тesting page")
            }
            }
            .navigationBarTitle("Main page")
        }
    }
}

struct page3: View {
    @State private var selectedFlavor = Flavor.chocolate
    enum Flavor: String, CaseIterable, Identifiable {
        case chocolate
        case vanilla
        case strawberry

        var id: String { self.rawValue }
    }
    var body: some View {
        NavigationView {
            Form {
                Section {
                    Picker("Flavor", selection: $selectedFlavor) {
                        Text("Chocolate").tag(Flavor.chocolate)
                        Text("Vanilla").tag(Flavor.vanilla)
                        Text("Strawberry").tag(Flavor.strawberry)
                    }
                    Text("Selected flavor: \(selectedFlavor.rawValue)")
                }
            }
        }
    }
}

UPDATE: Find out that my console is trying to tell me: "Returning an empty, disconnected UIBarButtonItem to fulfill the non-null contract" I don't know what that exactly mean, but i found strange solution:

.navigationViewStyle(StackNavigationViewStyle())

Apple documentation doesn't say anything about it, but if you set it up like this:

struct ContentView: View {
    var body: some View {
        NavigationView {
            List{
            NavigationLink(destination: page2()) {
                Text("Food input")
            }
            NavigationLink(destination: page3()) {
                Text("Тesting page")
            }
            }
            .navigationBarTitle("Main page")
        }
        .navigationViewStyle(StackNavigationViewStyle())
    }
}

All problem will gone. Please explain me how it works, i really stuck in that.

struct ContentView: View {
    var body: some View {
        NavigationView {
            List{
            NavigationLink(destination: page2()) {
                Text("Food input")
            }
            NavigationLink(destination: page3()) {
                Text("Тesting page")
            }
            }
            .navigationBarTitle("Main page")
        }
        .navigationViewStyle(StackNavigationViewStyle())
    }
}