iOS Question B4XPages : Close button doesn't work for InterstitialAd

Sub Class_Globals
    Private Root As B4XView
    Private xui As XUI
    Private iad As InterstitialAd
End Sub

Public Sub Initialize
'    B4XPages.GetManager.LogEvents = True
End Sub

'This event will be called once, before the page becomes visible.
Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    Root.LoadLayout("MainPage")
    iad.Initialize("iad", "ca-app-pub-3940256099942544/4411468910")
End Sub

Private Sub Button1_Click
    iad.RequestAd
End Sub

Sub iad_Ready (Success As Boolean)
    If Success Then
        Log("iad is ready.")
        iad.Show(B4XPages.GetNativeParent(Me))
    Else
        Log("Failed to load full screen ad: " & LastException)
    End If
End Sub

Sub iAd_Closed
    Log("closed")
End Sub

Private Sub iad_AdClosed
    Log("adclosed")
End Sub

Private Sub iad_AdOpened
    Log("iad opened")
End Sub

Private Sub B4XPage_Resize (Width As Float, Height As Float)
    #if B4i
    Dim r As Rect = B4XPages.GetNativeParent(Me).SafeAreaInsets
    Root.SetLayoutAnimated(0, r.Left, r.Top, Width - r.Right - r.Left, Height - r.Bottom - r.Top)
    #end if
End Sub

<Google> Status bar could not be hidden for full screen ad. Ensure that your app is configured to allow full screen ads to control the status bar. For example, consider whether you need to set the childViewControllerForStatusBarHidden property on your ad's rootViewController.