it's the clothes and how they are rendered especially the very first panel
and i don't scrutinize details to identify AI images. call it artist's intuition or whatever but AI "art" looks and gives off a very different feeling to actual art. so although i could recognize AI images 80% of the time, i could still be very much wrong.
in this situation i'm only saying it looks AI because it is similar to AI images i have seen before.
Maybe don't call it ai and you won't get hate. You will be hurting any artist's feelings if you said their art looks like ai, they drew it with their damn hands, it's fault of people using ai who stole this art style and now you think it's alright to call this ai bc you saw all the ai art which stole this art style
idk folks, it's the first thing i've noticed. the shading in this manga looks ai-generated.