diff --git a/OpenRA.Game/Network/OrderIO.cs b/OpenRA.Game/Network/OrderIO.cs
index 3fc347160b..0c104d044f 100644
--- a/OpenRA.Game/Network/OrderIO.cs
+++ b/OpenRA.Game/Network/OrderIO.cs
@@ -54,13 +54,14 @@ namespace OpenRA.Network
 
 		public byte[] Serialize(int frame)
 		{
-			if (data != null)
-				return data.ToArray();
-
 			var ms = new MemoryStream();
 			ms.WriteArray(BitConverter.GetBytes(frame));
-			foreach (var o in orders)
-				ms.WriteArray(o.Serialize());
+			if (data != null)
+				data.CopyTo(ms);
+			else
+				foreach (var o in orders)
+					ms.WriteArray(o.Serialize());
+
 			return ms.ToArray();
 		}