Like others have mentioned, it would probably be best to specify the type of list you do want.
I know that at least for image generators, they can often have trouble when specifying the absence of something, as illustrated here, where asking it to create a plate with ‘no bananas on it’, it generates a plate with bananas.
So I would experiment with not even mentioning the numbered lists, because I’d wonder how much of the training data would be something like “here is a list that is not a numbered list” lol.