Sorry, yes, "Note" should have been "Not" as you guessed.
I'm not absolutely sure, but I believe that the old state was that when you looked at "your" submissions, you could edit them directly (even through they were not "owned" by you). I'm pretty sure that people have been editing those w/o having to ask Q+A Editors to do it for them.
Perhaps somebody who has tried that more recently than I could chime in (but tried before these recent changes).
So my guess is that there was code in 'editinvote' (or somewhere) that honored original_author not just author_user.
In reply to Re^3: Editing your writeup is now a separate action from viewing a thread and voting on replies (original_user)