You can turn up the eo config and see what the engine is doing.
Attached is a neutered process log showing a message as it goes through the outbound thread. The portion you are interested in is really at the bottom.
You’ll see it receives a response from the FTP server that says (in my case) 226 Transfer complete.
I believe that is the answer to your question because it then invokes the send ok procs.
You can also create a custom eo config that includes only fset and pd which should give you enough information to track further.
I’m very interested in your results because I can’t believe that Cloverleaf would loose a message. I’m sure I haven’t lost any.
Let me know what you find,
-mh