It seems a tweak or two was made for Lists in RC17, but the bug with copy-paste in an empty list line is still present in RC17 and 18.
Here is the problem. Just after you press Enter to make new list item, Scrivener creates it, as expected, with new auto-number at the beginning of the line (img 01).
[attachment=2]IMG 01 – before pasting.png[/attachment]
While the line is empty (no symbol, no space), if you try to paste some text there by Ctrl+V, you will destroy autonumbering (img 02), which is hardly what you expect.
[attachment=1]IMG 02 – Ctrl-V – error.png[/attachment]
NB 1: If you press Ctrl+Shift+V instead of Ctrl+V, all works fine (img 03).
[attachment=0]IMG 03 – Ctrl-Shift-V – ok.png[/attachment]
NB 2: You cannot get back to previous state by Ctrl-Z.
This could only be considered, if a paragraph pasted would not be a list item. I expected my images to show it quite clearly that the text was copied from one list item and pasted to the next one of the same level. It means just the same formatting. Not to say, it is a point to discuss whether belonging to the list and list level is a part of formatting. Anyway, it doesn’t matter where you copy your text from in this case.
What is more, to talk if this is what one expects, let’s try to do the same thing in Word or Libre Office.
Update: Come to think of it, that doesn’t entirely surprise me either. (Why? Because of the part my video doesn’t explain.) When you press enter in a list, Scrivener not only formats the new paragraph the same as the last, but it also generates the appropriate bullet, and I don’t know how that happens.
(1) The mysteries like that are exactly what people call ‘bugs’.
(2) I doubt that ‘Scrivener generates the appropriate bullet’ is a proper explanation for how it works.
(3) If you are interested in this specific case, you could try another mysterious thing: if you have at least one symbol, including space, at the new line, Ctrl+V works as everybody expects, i.e. doesn’t ruin the list item.