Designers republic and memphis were the only designs i couldn't immediately see were AI generated.
The only reason i couldn't tell memphis is because it's aping a known design language already, it's just a perfect copy so me not being able to tell it wasn't AI isn't a free pass in this case.
I think if there was a little less "grid" feeling to the layout details then i wouldn't be able to tell on a few of the other designs either.
Edit: the designers republic version is quite a lot different than the others, it's not just that it's the only design to avoid pairing every feature with an icon, it's the whole layout variety - there's different font sizes, the positioning of elements is very well done to my eye. I'm gonna say this has to be another case like memphis, there's some pre-existing design language that i don't know of and it's just aping that. It's much more human than the others which i can believe are straight ai.
What is the tell on the punk one?
I'm not the GP but if you look at actual 1980s zines the difference is obvious, even if it's not easy to put into words. The absence of photos or hand-drawn graphics in particular.
The origins of the punk movement are in counterculture and DIY, so there's something particularly perverse about using an AI model to generate a poster in that style.