This case is specific, I guess? It's been a recurring problem for me even before the new layout was in place.
I have a file which I want to submit. See, before the new layout went online, I attempted to submit the file once onto NG, and it was on. Then I had second thoughts and removed it. Then, some time later (maybe a few weeks later), I resubmitted the audio onto NG again, and then I had second thoughts and removed it again.
Now, whenever I want to submit that same file onto NG again, it displays an error message.
Ever since then, I've been trying to resubmit that file (and now I have no second thoughts of putting it up!), but because of that error message, I have created several project files for the same piece of music.
The audio works fine in Preview Stage, though: