The other thing that is characteristic of AI text is messing up the underlying meaning or fine details of what it's saying. It's not just that it's imitating people who write bad contrasting clauses, it also can't write good ones reliably.

edit: Ironically that last sentence is not super clear (but hey writing is hard and I'm constantly exposed to slop). My point is the nature of AI makes its writing worse than its training data, it's not all bad training data.