I mean, yeah, I can see why readers outside Indonesia would be confused and pronounce “Cahaya” as “Kahaya.” But the correct spelling really is Cahaya, and it’s pronounced “ca-ha-ya.”
“Cha Haya” also sounds a bit strange to Indonesian ears. So I kinda wonder why they didn’t just write it as “Cahaya” even if the Hangul uses “cha,” and then explain that it’s still pronounced the same as the Indonesian “ca.”
Well… I guess we’ll just have to wait for the official translation.

His name is cahaya not cha haya...
Cahaya means "light" and matahari means "sun".