I see what you’re being thrown by, sort of, I’ve never really used that mode of creation, I tend to go into edit mode Fn+Edit and create new chain lines there (or quick on the fly style)
Doing it the way that you detail it brings up a blank line along the bottom, in that menu it will chain if you select and hold multiple patterns, however, that is at odds with the wording there
the behaviour of patterns/scratch in general was subtly tweaked in the last OS, see release notes for that, it may be relevant
I think the issue you found may be valid after all, either relating to the exact wording or current implementation - I’m not chaining that way so I can’t comment on whether it has changed - I always quick chain
I think the you’re probably right after all (agree re wording), but I’m not really a heavy chain user, see if a chain guru can shed some light on it - it’s all a bit finicky in that menu with cursors and highlighted lines and scratch lines and chain lines