A new user reposted a question after a couple of hours. He responded to the "possible duplicate of..." comment left by the first close vote with a comment saying
sir i haven't got any answers for this question...could you please help me to find out. I cast the fifth close vote and tried to post a response telling him how to edit the original question rather than reposting, but I couldn't post the comment because apparently the question had already been deleted, within a minute of being closed. I followed the link to the original question in order to post the comment there, but that one was gone too. I know it was definitely still there a couple of minutes earlier because I visited it while doing the review. I thought maybe for some reason the user had been deleted, causing both questions to disappear simultaneously, but the account is still there.
As far as I could tell it was a legitimate question, on-topic and complete with code, an image demonstrating the problem, and a clear explanation. Did each get deleted as a duplicate of the other by mistake (in which case one of them should be restored), or was there some reason they were both whacked?
(The embedded image didn't have any freehand red circles, but if I'm not mistaken that's only considered grounds for deletion on meta.)
I realize there's a feature to identify questions mutually closed as duplicates, but that doesn't apply here because only one was closed, and they were both deleted.