Bug Amazon store: Unity IAP doesn't fire any callback if non consumable product is purchased twice

On Amazon store, if a non consumable product is purchased twice, Unity IAP doesn't fire any callback.
On Google Play, OnPurchaseFailed is called with PurchaseFailureReason.DuplicateTransaction.
See attached log screenshot : Unity Purchasing Amazon log "ALREADY_PURCHASED" but OnPurchaseFailed is not called.
Tested on Unity 2020.3.21f1 and IAP 4.0.3

 

I use the Scripted IAP the common way.
Below is an extract of my purchase manager (simplified):

Code (CSharp):

1. public class PurchaseManager : Singleton<PurchaseManager>, IStoreListener
2.     {
3.         protected IStoreController m_StoreController;
4.         protected IExtensionProvider m_Extensions;
5. ...
6.       void Start()
7.         {
8.             InitializePurchasing();
9.         }
10.  
11.         void InitializePurchasing()
12.         {
13.             var builder = ConfigurationBuilder.Instance(StandardPurchasingModule.Instance());
14.             builder.AddProduct("XXXXXX", ProductType.NonConsumable);
15.             UnityPurchasing.Initialize(this, builder);
16.         }
17.  
18.       public void OnInitialized(IStoreController controller, IExtensionProvider extensions)
19.         {
20.             m_StoreController = controller;
21.             m_Extensions = extensions;
22.  
23.             if (Application.platform == RuntimePlatform.IPhonePlayer)
24.                 m_Extensions.GetExtension<IAppleExtensions>().RegisterPurchaseDeferredListener(OnDeferred);
25.         }
26.  
27.         public void OnInitializeFailed(InitializationFailureReason error)
28.         {
29.             Debug.Log($"In-App Purchasing initialize failed: {error}");
30.         }
31.  
32.        public void Purchase(string packName)
33.         {
34.                m_StoreController.InitiatePurchase(packName);
35.         }
36.  
37.        public PurchaseProcessingResult ProcessPurchase(PurchaseEventArgs args)
38.         {
39.             Product product = args.purchasedProduct;
40. ...
41.             return PurchaseProcessingResult.Complete;
42.         }
43.         public void OnPurchaseFailed(Product product, PurchaseFailureReason failureReason)
44.         {
45.             Debug.Log($"Purchase failed - Product: '{product.definition.id}', PurchaseFailureReason: {failureReason}");
46.         }
47. }

 

Yes of course.
The only situation that may need this to work is if you have 2 devices and you have purchased an item on one of them.
The only way to unlock the purchase on the second device is to purchase it again (and then, with the "ALREADY_PURCHASED" error, we can unlock it as a restore solution)...

 

@JeffDUnity3D I have a little bit outdated setup to play with Amazon (2018 LTS, asset store 2.2.7 + com.unity.purchasing 2.2.2), but if you want to take some more info into consideration, my subsequent purchase of non-consumable product (which is known as "Entitlement" at IAP dashboard) also results in "ALREADY_PURCHASED" log from Unity Purchasing Amazon sender, but instead of @Knbmedia 's no-reaction result I do get ProcessPurchase called, but with an empty transaction id.

I guess there had to be PurchaseFailed call with DuplicateTransaction reason equal to GooglePlay behaviour.

The same goes for subsequent subscription purchase.