I think you're missing the fact that Sex IS the contract. Literally. And it's still active. It's the thing holding their relationship together rn. Them having sex isn't surprising or even an issue... HOW they have sex is what matters, so the next chapter is going to be very revealing.
also, if you can't see the difference between this and season 1, you're reading with your eyes closed (respectfully)
consent isn't a blanket statement. disregarding whether or not the contract = sex (i still believe it doesn't), even if it was, it's still considered assault if dan withdraws his consent during sex. but we don't know bc jk didnt ask. if jk had even made sure if everything was okay considering that fact he saw dan not eat dinner, i wouldn't be complaining at all.
just to let you know i'm ignoring dan saying that his body's responding to jk's touch bc that line has been used as a tool time and time again to glamorize assault and doesn't apply to real life standards.
and respectfully i CAN tell the difference between this and s1 and it’s disappointing how similar this still feels, especially after chapters of supposed growth. if jk really is evolving, he needs to show it in the moments that matter most, like this one

jk's jinx is his biggest character flaw. it stemmed from his anxiety of becoming a loser and rooted in childhood trauma. since it's already been established that jk can't have sex with anyone other than dan to satisfy his jinx, and that dan plans to leave once/if jk wins championship, you'd think jk has a backup plan when his only cure disappears. but with the way the story is handling jk's writing.... i wouldn't be surprised if he finds some loophole to force dan to stay. i think it's SO so important that jk intentionally and purposefully lets dan go, not bc jk blows up at him again, not bc dan runs away, but bc jk respects dan's autonomy.
with their contract's end looming over him, jk should honestly be working on fixing his jinx or finding a substitute (not a human substitution, but a completely different action). he knows he's in love with dan and that he's treated him poorly in the past; yet instead of finding something else to serve as his jinx, he reverts back to using dan. but what's obvious in this chapter is that jk doesn't want to sleep with dan bc of the jinx. he simply finds dan sexually and and physically attractive. and he just really likes the guy. i really don't think he cared about his jinx once he kissed dan. but if it truly was about dan himself, it just makes the entire scene worse imo. if you really loved someone, wouldn't you want them to want you too? jk KNOWS what consent is, we've seen him demonstrate that when he was drunk, so then why didn't he make sure the person he loved was okay with having sex with him? them having sex was inevitable (though disappointing) but with the absence of consent you could've told me this was from season one and i'd be none the wiser.
this entire story is set at jk's pace. he decides when and where to have sex, he's the one that causes dan to run away, and he's the main reason dan returns. dan is simply strung along left to make choices that aren't really choices. the last few chapters were the first time in this story where jk had actively put in the effort to walk at dan's pace--not having sex, going to amusement park, playing those board games. so this chapter was a slap in the face.
also i think it's important to remember their contract was: help jk win the championship and he'll get rid of the only connection left between him and dan. dan didn't agree to sex, he agreed to be let go. honestly the only way they can salvage their relationship is if jk succeeds in putting dan's wellbeing over his own obsession with his jinx. AND TO FIX THAT DAMN JINX
that's the end of my ted talk