No, it’s not a bad joke. I’ve seen a few instances where a Mod will post a message like, “Per the request of the OP, I am closing this thread”.
Sometimes, though, it is followed by ANOTHER Mod who has posted the same message.
Is it just a matter of timing (it has happened more than once)?
Or did the first Mod not lock the thread correctly? (I’m not saying the Mods are not perfect. No, no, no, I would NEVER say that, heh, heh, :D)
We’re at the mercy of the hamsters* the same as everyone else. Sometimes we get that “Cannot find server” message when we’re closing or moving a thread, the same as y’all do when you’re trying to post.
*And the Internet in general, and our ISP’s, and the Microsoft Corporation, and our own PC’s…
I’d guess it’s a timing issue. Sometimes you’ll see regular posters posting up to several minutes after a Mod has posted that they’re closing the thread. I’d imagine that closing a thread has to go through the server like any other action, so sometimes it takes a little while to register.
Err, yeah.
If the timestamps on the two “I’m closing this thread” posts by the Mods are identical or off by just a few minutes, it’s probably what White Lightning suggests; a Moderator simul-post. (Actually, if two of us try to simultaneously close the thread, one could wind up closing it and then the other could immediately re-open it, because the “Open / Close Thread” option is just that: it toggles the thread to closed or open, depending on which way the thread is when the command is given.)
If Mod A posts “I’m closing this thread”, other people post, and then Mod B posts “I’m closing this thread” two hours later, something probably happened to interrupt Mod A or prevent him or her from finishing the closing of the thread. Naturally, this could not be the result of human error on the part of Mod A, since we Mods are far above mere humanity, so presumably the entire Internet crashed.
In a recent IMHO thread, it happened because two mods posted then tried to close a thread at approximately the same time. What happened was exactly what MEBuckner posted above. 
That’s what I figured. Although, secretly, I was hoping it was some kinda internal battle:
“You call THAT closing a thread? HA! I’LL show YOU how to close a thread.”
'T is true that some of us have more style when it comes to closing threads. But we still like MEBuckner just fine, honestly.