I found the fix in this thread.
If PHP had namespaces that matched the filenames, it wouldn’t be such a pain to find out what functions were in which files.
For the benefit for anyone else that finds this thread, I found the wpautop function in functions-formatting.php.
And the fix worked.
I have the same annoying problem. Grr.
Thanks, Moose, I’ll try that. 🙂