As an artist myself, it doesn't look like ai to me at all, the page you mentioned just has a panel that looks like they added filters and/or overlay layers. If you duplicate the layers, use grausian blur on the copies and turn those into overlays, you get the exact effect that makes the art on that page look different from the other panels.
PLEASE DON'T JUST BASELESSLY THROW AI ACCUSATIONS JUST BECAUSE OF THE RENDERING STYLE

Ngl in this last chapter one of the panels looked like ai but I could also just be hallucinating