Fix RabbitMQ double acknowledgement on InvokeAsync deserialization exceptions

src/Transports/RabbitMQ/Wolverine.RabbitMQ/Internal/RabbitMqChannelCallback.cs

@@ -99,7 +99,9 @@ private async Task moveToErrorQueueAsync(RabbitMqEnvelope envelope, Cancellation
         {
             if (envelope.RabbitMqListener.Channel is not null)
             {
-                // For idempotency
+                // Mark as acknowledged before the NACK so that any subsequent
+                // CompleteAsync() call is a no-op (prevents double ack/nack)
+                envelope.Acknowledged = true;
                 envelope.HasBeenAcked = true;
                 await envelope.RabbitMqListener.Channel.BasicNackAsync(envelope.DeliveryTag, false, false, token);
             }

src/Transports/RabbitMQ/Wolverine.RabbitMQ/Internal/RabbitMqEnvelope.cs

@@ -21,10 +21,12 @@ internal void OverrideDeliveryTag(ulong tag)
     internal RabbitMqListener RabbitMqListener { get;  }
     internal ulong DeliveryTag { get; private set;}
 
-    public bool Acknowledged { get; private set; }
+    public bool Acknowledged { get; internal set; }
 
     internal async Task CompleteAsync()
     {
+        if (Acknowledged) return;
+
         await RabbitMqListener.CompleteAsync(DeliveryTag);
         Acknowledged = true;
     }