Still not quite working, but pushing my change

Author: jonathanpeppers

source/com.android.billingclient/billing/Additions/Additions.cs

@@ -4,6 +4,18 @@
 
 namespace Android.BillingClient.Api
 {
+    public partial class BillingResult
+    {
+        internal BillingResult Clone()
+        {
+            return BillingResult.NewBuilder()
+                .SetResponseCode((int)ResponseCode)
+                .SetDebugMessage(DebugMessage)
+                .SetOnPurchasesUpdatedSubResponseCode(OnPurchasesUpdatedSubResponseCode)
+                .Build();
+        }
+    }
+
     public class ConsumeResult
     {
         public BillingResult BillingResult { get; set; }
@@ -196,7 +208,10 @@ internal class InternalAcknowledgePurchaseResponseListener : Java.Lang.Object, I
         public Action<BillingResult> AcknowledgePurchaseResponseHandler { get; set; }
 
         public void OnAcknowledgePurchaseResponse(BillingResult result)
-            => AcknowledgePurchaseResponseHandler?.Invoke(result);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            AcknowledgePurchaseResponseHandler?.Invoke(result.Clone());
+        }
     }
 
     internal class InternalBillingClientStateListener : Java.Lang.Object, IBillingClientStateListener
@@ -209,36 +224,51 @@ public void OnBillingServiceDisconnected()
             => BillingServiceDisconnectedHandler?.Invoke();
 
         public void OnBillingSetupFinished(BillingResult result)
-            => BillingSetupFinishedHandler?.Invoke(result);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            BillingSetupFinishedHandler?.Invoke(result.Clone());
+        }
     }
 
     internal class InternalConsumeResponseListener : Java.Lang.Object, IConsumeResponseListener
     {
         public Action<BillingResult, string> ConsumeResponseHandler { get; set; }
         public void OnConsumeResponse(BillingResult result, string str)
-            => ConsumeResponseHandler?.Invoke(result, str);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            ConsumeResponseHandler?.Invoke(result.Clone(), str);
+        }
     }
 
     internal class InternalPriceChangeConfirmationListener : Java.Lang.Object //, IPriceChangeConfirmationListener
     {
         public Action<BillingResult> PriceChangeConfirmationHandler { get; set; }
         public void OnPriceChangeConfirmationResult(BillingResult result)
-            => PriceChangeConfirmationHandler?.Invoke(result);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            PriceChangeConfirmationHandler?.Invoke(result.Clone());
+        }
     }
 
     internal class InternalPurchaseHistoryResponseListener : Java.Lang.Object, IPurchaseHistoryResponseListener
     {
         public Action<BillingResult, IList<PurchaseHistoryRecord>> PurchaseHistoryResponseHandler { get; set; }
 
         public void OnPurchaseHistoryResponse(BillingResult result, IList<PurchaseHistoryRecord> history)
-            => PurchaseHistoryResponseHandler?.Invoke(result, history);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            PurchaseHistoryResponseHandler?.Invoke(result.Clone(), history);
+        }
     }
 
     internal class InternalPurchasesUpdatedListener : Java.Lang.Object, IPurchasesUpdatedListener
     {
         public Action<BillingResult, IList<Purchase>> PurchasesUpdatedHandler { get; set; }
         public void OnPurchasesUpdated(BillingResult result, IList<Purchase> purchases)
-            => PurchasesUpdatedHandler?.Invoke(result, purchases);
+        {
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            PurchasesUpdatedHandler?.Invoke(result.Clone(), purchases);
+        }
     }
 
     [Obsolete("Use QueryProductDetailsAsync(QueryProductDetailsParams) instead")]
@@ -256,7 +286,8 @@ internal class InternalProductDetailsResponseListener : Java.Lang.Object, IProdu
 
         public void OnProductDetailsResponse(BillingResult result, QueryProductDetailsResult queryResult)
         {
-            ProductDetailsResponseHandler?.Invoke(result, queryResult?.ProductDetailsList);
+            // Create a copy of the BillingResult to ensure it stays alive after the callback
+            ProductDetailsResponseHandler?.Invoke(result.Clone(), queryResult?.ProductDetailsList);
         }
     }