I don't think they've totally reverted back, this blowup was just inevitable. I love that they triggered each other and it went sour so fast. Their communication has improved but imo they don't trust other people to not hurt them. Skylar avoids intimacy & Cirrus doesn't get the reassurance he wants from him.. so he goes behind Skylar's back to isolate him from others. He doesn't trust that Skylar would choose him.
Cirrus has also ignored Skylar's anxiety all season & is now showing his jealousy clearly, shouting loudly, & bringing up Minwoo so Skylar goes defensive instead of trying to make Cirrus understand again. Tbh I was surprised he punched him too but he's done it before & his violent tendencies haven't rly been addressed yet so this is a good time to bring it back.
I'M GONNA BE SICKKKKKKKKKKK HAVING CIRRUS BE SO SCARED SKYLAR'S GONNA BREAK UP WITH HIM JUST FOR SKYLAR TO SAY IN THE LATEST CHAPTER HE'S DATING CIRRUS BC HE CAN'T DATE CHAN IL..............SIIIICCKKKKKKKKKKK JUST SICK