diff --git a/Assets/Mirror/Tests/Editor/NetworkServerTest.cs b/Assets/Mirror/Tests/Editor/NetworkServerTest.cs
index afa2213af..7a1c8961f 100644
--- a/Assets/Mirror/Tests/Editor/NetworkServerTest.cs
+++ b/Assets/Mirror/Tests/Editor/NetworkServerTest.cs
@@ -11,8 +11,11 @@ struct TestMessage1 : NetworkMessage {}
 
     struct VariableSizedMessage : NetworkMessage
     {
+        // weaver serializes byte[] wit WriteBytesAndSize
         public byte[] payload;
-        public VariableSizedMessage(int size) => payload = new byte[size];
+        // so payload := size - 4
+        // then the message is exactly maxed size.
+        public VariableSizedMessage(int size) => payload = new byte[size - 4];
     }
 
     public class CommandTestNetworkBehaviour : NetworkBehaviour