Scrivener (RC5) is “correcting” the proper name Taine (an inter-war SF writer, whose work I’m describing, so I can’t change it) to Taîné, even though I have no such correction in my list of additional substitutions.
What is really weird is that it only it after I type two keystrokes after Taine, whereas all other auto-corrections happen after one.
I’m using the UK English spelling check.
Curious to know if anyone can reproduce this?
Also, is there an editable list of built-in autocorrect entries that can be altered; I can’t find it, if there is.
The horrors of Autocorrect! I would guess the two strokes is because the last é is accented, but then what do I know?
I have spell-check turned off completely in Scrivener; I prefer to do that in Nisus Writer Pro after compiling, but that aside, I can think of two work-arounds:
In replacements have ‘Taine’ as input and ‘Taîné’ as output, setting ‘respect letter case’ or whatever it might be called, then type 'Taine" as you’re going along, leaving Scrivener to do the replacement—of course you could use some abbreviated trigger as input;
try temporarily turning off “Correct spelling as you type” or whatever it’s called in Windows, type “Taîné”, select “Check Spelling” and when it picks it up, choose “Learn”.
Thanks for the suggestions Mark, but fixing it isn’t hard (you just hit Ctrl-Z and it undoes the correction). I was more interested in the mechanics of where/how these entries are stored? (And what was the person who wrote them smoking when they wrote them…)
That’s OK, JJE. Cmd-Z—the Mac equivalent to Ctrl-Z—works here, but I always forget to do it immediately, which is why I’d teach spell-check to recognise such expressions, though as I said, I do that in NWP … Mac-only wp … basically I gave up Word after v. 5.1a for the Mac. With v. 6 for Mac in the naughties, Microsoft gave up all the things that made 5.1a so brilliant—I’d still be using it now if I could!—to bring it into UI-identity with the far less useable Windows version of the time.
The weirdest thing about this “correction” is that “Taine” is my dictionary so it isn’t marked as misspelt in the first place! I could do a reverse auto-correct (i.e. change Taîné back to Taine, but I’m really more curious about why/how this is happening in the first place.
More bizarre yet is that I’m not sure “Taîné” is actually a real word or name. When I search online for it, all I get are badly digitized French texts in the Internet Archive, where it is clearly a transcription error. This almost seems like some sort of prankish Easter egg. I think the question about smoking may in fact be relevant.
Scrivener doesn’t, as far as I know, have any internal sources of words. It uses the downloaded dictionary (or something you downloaded and replaced it with, if you’ve done that), the substitutions list, and your personal word list. So far as I know, that’s it. Those are the three sources it should be using for any substitutions or corrections.
I just tried to replicate this, and could not. Are you using a special dictionary of any sort? Or just the standard one it downloads for the UK?
I would guess the two strokes is because the last é is accented, but then what do I know? 
