Is This a bug of iOS 15 with SwiftUI?

//
// ContentView.swift
// Shared
//
// Created by Abenx on 2021/8/8.
//

import SwiftUI


/// Demo of NavigationLink causing page problems
///
/// Problem description: When the following structure is used, after entering level3. If the app loses focus, such as drawing out of the control center or multi-page manager, it will cause the page to refresh and render, and eventually jump to level 2.
/// iPhone 12 Pro Max / iOS 15 beta 4 has this problem
/// iPhone 12 Pro Max / iOS 14.6 has no such problem
/// Xcode Version: 12.5.1 (12E507) & 13.0 beta 4 (13A5201i)

struct ContentView: View {
  /// If you comment out this line of code, there will be no problem.
  @Environment(\.openURL) var openURL

  @State private var isOK: Bool = false
   
  var body: some View {
    NavigationView {
      NavigationLink("Goto Level 2", destination: Level2View().onAppear {
        /// If you comment out this line of code, there will be no problem.
        isOK = false
      })
    }
  }
}

struct Level2View: View {
  var body: some View {
    /// If you don't use GeometryReader, there is no problem.
    GeometryReader {proxy in
      NavigationLink("Goto Level 3", destination: Text("I am in Level 3"))
    }
  }
}

struct ContentView_Previews: PreviewProvider {
  static var previews: some View {
    ContentView()
  }
}