Just posted a reply in a MYOG thread.
I think I must have double submitted – I’m on a laptop where that is quite easy to do.
I’m not entirely clear on the sequence but the double submission protection didn’t seem to work properly.
I was shown a red error message saying it was a duplicate. I’m afraid I didn’t check if the first submission had posted. I re-submitted, and this time the exact duplicate was accepted and I had to edit it out once I realised what had happened.
Sorry not to be clearer, but I do think you need to check the code.