SSO with Google 2fa account in WKWebview using ASWebAuthenticationSession not working right

Question

We have a web app which has two single sign-on options sign-in with apple and sign-in with google which all works fine in the browser. On iOS we have this web app in WKWebview app shell in which we use ASWebAuthenticationSession for sign-in with google.

The problem comes here only when the user has 2 factor authentication on his/her google account, the ASWebAuthenticationSession window doesn't close after 2 step verification, It loads the web app in its own content.

some how it seems like the ASWebAuthenticationSession configuration prefersEphemeralWebBrowserSession = true gets lost in the process.

Anyone with any Idea on how we can fix this problem?

Thanks.

here is the swift code

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    guard let url = navigationAction.request.url else {
      decisionHandler(.cancel)
      return
    }
    if(Functions.getParameter(url: url.absoluteString, param: “code”) != nil){
      authSession.cancel() // close login window
      ......*webView load url*
    }
    else{
      if let url = webView.url, url.absoluteString.starts(with: “https://accounts.google.com”){
        let callbackScheme = “https”
        authSession = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackScheme, completionHandler: { (callbackURL, error) in
          return
        })
        authSession.presentationContextProvider = self
        authSession.prefersEphemeralWebBrowserSession = true
        authSession.start()
        decisionHandler(.cancel)
        return
      }
    }
   decisionHandler(.allow)
  }