I'm a little confused. Has the "this question has been sent back for editing" message been replaced with a "this discussion is closed" message?

Those are two different situations.
“This discussion is closed” means that the question is, for one reason or another, not coming back. Maybe the user deleted it, maybe the mod rejected it, maybe @timtrueman’s seahorses ran away with it.
“This question has been sent back for editing” means that it is somewhere in the process between being sent to editing and being accepted.

@Sarcasm Except that two of the “this discussion is closed” questions did come back. Maybe the OPs abandoned their initial questions and ask similar questions later?

Without knowing specifically which questions you mean, I’d assume that’s the right assumption. I have seen a few people recently abandon a question to re-ask it more appropriately.
I just censored one of my own and it showed as “Sent back for editing”.

@Sarcasm I’ll pm you with the questions I’m talking about.

This is a brand new system, and we’re still working out the kinks. I think, at the moment, a question in editing will say both things (‘closed’ and ‘editing’). That might be a tad confusing. Sorry about that!

@augustlan So maybe I’m not just imagining this? Well, whatever is going on, I hope you all get it straightened out soon because I am kept plenty busy straightening out the confusion I cause myself and I really don’t need any outside agitators coming around and mucking things up even more. :-)

@lillycoyote I just checked on a question in the editing process, and yep… it says both. You’re not imagining it. :)

Thanks @augustlan! That clears things up sufficiently. I’ve gotten to the age where any answer that assures me that I have not simply gone senile is good enough for me. :-)

You have cutlery for an avatar instead of the painting you’ve had for years. You do know that, right?

@seazen Yes, I do know. And, they’re not just cutlery, they’re sporks. I had a pumpkin avatar for Halloween and I am having some computer issues. My regular avatar is on my Mac and I don’t have a working keyboard for it right now and my other computer has issues too, so I’m on old laptop for now . It was either the sporks or having people think I didn’t have the sense to take off my Halloween costume.

We can DELETE OUR QUESTIONS NOW! that’s AWESOME!

@iamthemob I see where you got that impression but really what he meant to say was “maybe the user abandoned their question in the editing process”. Sorry, no deleting your questions as that would involve deleting other people’s hard work as well. If you really want it removed, flag and it explain why. This is unchanged/unaffected by this tweak to the editing process.

You still see “this question is in editing” at the top of a question if it’s being edited. In the answer area, for both questions that have been closed or rejected, you’ll see “This question is closed” instead of a place to respond.

There are also questions that have been archived.

I kind of love how @andrew is always looking at his posts…as if he fears they’re coming over to “get him.”

@iamthemob LOL! You’re right!!! I never noticed that. Andrew’s avatar makes it look like he’s a little afraid of his own posts. That’s hilarious.