no the lemonade isn't poisoned, it's just both cale and kim rok soo dislike drinking it, occasionally og cale gets angry when he's served that drink. Ron serving the lemonade was him being curious how much cale "changed"
fuck i really miss the comedic tone of the webnovel ;-; while reading i'd always picture how the funny reactions would drawn if they were adapted but havent seen it come to life in this webtoon yet.. hopefully soon
@LuminousAzael@sonyaism from the webnovel, ron knows cale doesn't like sour things and he brings cale lemonade to lightly provoke him. since new cale knows ron's hidden power, he's scared enough to drink it and that's how ron can tell cale has changed a bit from before. it's sort of a running joke in the novel than cale is scared of ron and gets the chills every time ron does something even really small lol
even though it becomes clear to everyone except for cale that ron actually cares for him. when ron starts doing nice things for him cale always misinterprets-- cale's comedic misinterpretation of everyone is a big running joke in the webnovel, would recommend reading!
@Meo it's a big running joke in the webnovel that cale constantly preaches that he's lazy and is scared of the overpowered characters while he actually
ends up protecting everyone and getting powerful himself