IAP Purchase failed event does not work as expected!

Unity Services
,
1

I am working on an IAP feature in my iOS app, and when testing I found that the payment sheets takes a long time to show up. So I added a “wait panel”, which simply shows up until there is a successful or failed purchase. However, this is very inconsistent, some times the “wait panel” deactivates but other times it does not. When I debug the code, it seems like the OnPurchaseFailed event was not even called when an user cancels the payment sheet. Same for successful purchase

        public void BuyMonthlySubscription()
        {
            waitPanel.SetActive(true);
            m_StoreController.InitiatePurchase(ProductsCatalog.monthlySubscriptionId);
        }
       
        public PurchaseProcessingResult ProcessPurchase(PurchaseEventArgs args)
        {
            // Retrieve the purchased product
            var product = args.purchasedProduct;
           
            UpdateUI();

            isSubscribedText.text = purchaseInProgress ? "Processing" : "You are subscribed";
           
            waitPanel.SetActive(false);
            // We return Complete, informing IAP that the processing on our side is done and the transaction can be closed.
            return PurchaseProcessingResult.Complete;
        }
        public void OnPurchaseFailed(Product product, PurchaseFailureReason failureReason)
        {
            waitPanel.SetActive(false);
        }
       
        public void OnPurchaseFailed(Product product, PurchaseFailureDescription failureDescription)
        {
            waitPanel.SetActive(false);
        }

   
        void UpdateUI()
        {
            var subscriptionProduct = m_StoreController.products.WithID(ProductsCatalog.monthlySubscriptionId);
            try
            {
                // updates texts with subscription info
            }
            catch (StoreSubscriptionInfoNotSupportedException)
            {

            }
            waitPanel.SetActive(false);       
        }