When using LoadSceneMode.Additive, the next scene with ARkit is not working properly?

When I click ViewAR it Loads the next scene

Code (CSharp):

1. SceneManager.LoadScene("scene2", LoadSceneMode.Additive);

In the second scene I am using ARkit to detect a plane and using UnityARHitTestExample I am placing an object on the detected plane.I cannot place objects on the plane but if I use

Code (CSharp):

1.  Loadscene.Single

in the above code it works smoothly.

The reason I am using LoadSceneMode.Additive is that when I hit back button from the scene 2 it should go exactly where I left in scene 1.That is if my scene 1 contains two pages,at start if I hit next it reaches second page.In the second page I have ViewAR button which when clicked goes to scene 2.From scene 2 when I hit back button it should return to page 2 in scene 1.

Code (CSharp):

1.  public void ViewAR()
2. {
3.     PlayerPrefs.SetInt("Option", Buttonoption);
4.     ProductDetails.SetActive(false);
5.     ViewARbtn.SetActive(false);
6.  
7.     StartCoroutine(Changescene());
8.  
9.     SceneManager.LoadScene("Scene2", LoadSceneMode.Additive);
10.  
11.  
12. }
13.  
14. IEnumerator Changescene()
15. {
16.  
17.     SceneManager.UnloadSceneAsync("Scene1");
18.     yield return new WaitForEndOfFrame();
19.  
20. }

The problem here is two scenes are interfering when I use Additive is what I think.I do not want to reload the first scene at the same time I cannot use

Code (CSharp):

1.  LoadSceneMode.Additive

.Any solution on how to get back to scene 1 when I hit back button in scene 2?