Responses
Yeehyeon found out about the "Changing" through Shushu. Shushu unintentionally revealed it under the impression that YH is aware that Kun is changing him.
huuuuge spoiler down below, but it'll take a bit of time for him to figure it out.
https://www.mangago.me/home/mangatopic/21804277/
Give me spoilers how long and how does he figure out he’s an omega