I'm afraid I don't have hash that was submitted many times, each one successful, but I'll note it if I see it happen again.  The exchanges where my client calculated the same hash twice and the server rejected it twice each looked like this:

Hi,

I decided not to report this when I noticed it, because I was concerned somebody would find a way to exploit it, but I imagine it's better to get it fixed:

I used rpcminer-cuda, which reports the hashes it finds.  Within the past few days, one of my miners found the same hash a number of times in a row, and the server accepted it each time.  It seems the server is sometimes assigning duplicate work?

EDIT: This just happened again, but this time the duplicate hashes (including the first) were rejected by the server.  (result: false, error: null).  Is is this an error on my side or on the server's side?