Update message-expiration.mdx

Address Disco feedback from #1605 (review)

Author: zainbacchus

pages/interop/message-expiration.mdx

@@ -50,6 +50,8 @@ The process to reemit an expired message:
 
 2.  [Relay the new message](/interop/message-passing) as normal.
 
+Note: Re-emitting an already relayed message will have no effect on the destination chain since the re-emitted event won't be logged by OP-Supervisor. 
+
 ## Next steps
 
 *   [Build a revolutionary app](/app-developers/get-started) that uses multiple blockchains within the Superchain