Why does onChange(of: authManager.authState) in View1 not fire when I change authState in View2?

struct View1: View {

  @Environment(AuthManager.self) var authManager

var body: some View {
  NavigationStack {
    VStack {
      Text("\(authManager.authState)")
    }
    .onChange(of: authManager.authState) {
      print("Changed")
    }
 }
}
}



struct View2: View {

   @Environment(AuthManager.self) var authManager

var body: some View {  
   NavigationStack {
      VStack {
        Text("\(authManager.authState)")
          .onTapGesture {
              if authManager.authState == .signedIn {
                authManager.authState = .signedOut
              } else {
                authManager.authState = .signedIn
              }
         }
     }
  }
}
}



@Obersvable class AuthManager {
  var authState: AuthState = .signedout
  ...
}



struct ContentView: View {
   @State private var authManager = AuthManager()

 var body: some View {
    MainTabView()
      .environment(authManager)
 }
}