Wait I don't remember why was he mad at him on the snowy night? Which chapter was it?

I dont remember what chapter, but black haired is mad at light brown haired cause light brown haired kept making videos with yoona (a woman he traded his staff with) even though he said that he will do grocery shopping with black hair. And perhaps he's mad because of that

Ch 20
Heejae went MIA and then Seyoung saw him make vids with Yoona. He assumed Heeja was dating Yoona and basically was like "Why am I putting up with him then"