jc wrote:(When I posted this reply, I got a weird sort of "bouncy" sponse, then nothing happened for about a minute. Then the page refreshed and showed two copies. Now I'm trying to figure out if this forum has a way to delete a message.

Occasionally happens to me. Once I even got told by the hopeful-submission page that there was a new message posted
which was my own.
I don't think it works after another message has posted, for us plebs, but in the same image cluster that includes the Re-Edit button (that you used) there's also a cross-button for deletion (which asks for a reason, maybe more useful for moderators than ourselves, but I tend to say why anyway - e.g. "This joke reply doesn't look as funny, thirty seconds after posting it.").
It wouldn't have been there on the message you edited (there was now a second post from you, blocking it) but it would have been seen on the second one (until someone posted something new, like this one!).
I think that would have been your answer, anyway. Until now, anyway. Now it's just a (potentially wrong) bit of advice for next time. Cancel the second message in a double-post. Quickly, before someone 'locks you in'. (Might not be allowed in Games subforum area?)
Edit: Four icons on this. Pencil (edit), Cross (delete, while applicable), Exclamation Mark (report
your own message? Actually, I've done that to ensure mods get an early adjudication on something I was having iffy thoughts about having posted) and Quotes (quoting. Natch.) And the original posting of this message took
me some time (whirly-browser time, that is) though in this case I left it rather than tried to reclick Submit.