Yep, clearly LLM assisted writing. It was likely prompted in stages, not one shot with a single prompt. I'm surprised you are basically the only one to notice. It seems most people need to literally see "not X, but Y" or "You're absolutely right!" to recognize it. Interestingly, I think it's gotten to the point that those who don't use LLM's or engage with LLM output often are unable to detect it.