In which chapter did Sayoung realized it was J?

Im pr sure sayoung knew basically the whole time

Chapter 43, when uijae went in eroded dungeon and sayoung was there too and uijae ran towards him and grab his face to ask if he is okay. Sayoung suddenly remember the warm hands from past and smile and his thoughts " I found him" And then the whole chapter he became clingy clingy

He always had suspicions and that eroded dungeon scene with J's warm hands confirmed it all.