pressing back button make fragment does not work nav component

Question

I am using nav component, just Activity Frag1,Frag2 , however moving from Frag1 to Frag2 is working, but When phone back button is pressed, Frag1 is appearing But nothing works, Clicklistner is nothing, init code does working

 class CarActivity : AppCompatActivity() {
       fun getLayoutId(): Int = R.layout.activity_car
    
      private lateinit var appBarConfiguration: AppBarConfiguration
    
      override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(getLayoutId())
        setSupportActionBar(toolbar_details)
    
        val navController = findNavController(R.id.nav_host_fragment_content_main)
        appBarConfiguration = AppBarConfiguration(navController.graph)
        setupActionBarWithNavController(navController, appBarConfiguration)
    
    }
    }

Activity

  <fragment
        android:id="@+id/nav_host_booking_fragment_content_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/nav_graph" />

nav_graph.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/nav_graph_cars"
    app:startDestination="@id/carFragment">
 


    <fragment
        android:id="@+id/Frag1"
    
        android:label=" ">

in activity

  override fun onSupportNavigateUp(): Boolean {
    val navController = findNavController(R.id.nav_host_fragment_content_main)
    return navController.navigateUp(appBarConfiguration)
            || super.onSupportNavigateUp()
  }

is seems like a new view is created, or a view is disconnected from fragment

using ViewBinding solve everything but ?