Well, this is a revolting development. I just wrote an offshoot of Addventure episode 820363, titled "OGOE: The Mu Mu Mixer" and numbered 823424, and I clicked "Create all new episodes" like I always do and then clicked "Accept," and then I got a page claiming that maybe I hadn't clicked "Create all new episodes" after all. I went back, clicked again, and it still made the claim. Is there anything there that's still salvageable, that might need generic future episode options plugged in, or will I just have to completely redo this later?
V to Adama below: thanks. I'm not even sure how I would check what you're talking about -- there was no telltale pause, I was led instantly to the page claiming I hadn't just clicked Create all new episodes.
Later: as I did it successfully just now, I remembered having written out the options before looking at a "Create all new episodes" button and automatically clicking it, so I'm guessing somehow the whole "redo your draft" option (which I rarely take advantage of -- and I have the typos to prove it) messed me up. Mystery solved.

(I like this emoticon better as a symbol of embarrassment, since I'm not feeling especially mournful over this.)

Oh, and I even got my own scribbled note wrong -- it was 823494, not 823424. (Dang, we're going to hit a million before we know it ... )
Later still: ehhh, MAYBE mystery solved, I still can't figure it out.