well technically it’s not wrong? i understand it like this: the mage asked him “what did SHE say ABOUT YOU (han)?” and han answered “a liar” and “you’re an idiot” in iolka’s perspective like she’s the one talking to han and he’s simply repeating it (idk if it makes any sense with other people or maybe you read the original untranslated version that’s why you reacted like that. but the translation made sense to me at least)
If it's written "she said you are an idiot" it means that Iolka said that her master is an idiot, otherwise they would have written "She said: you are an idiot" / "She said I'm an idiot" / She said <you are an idiot>"
I'm sorry, but if it's not a translation error, it's a grammatical error in English.
But the most likely thing is that since in korean the pronouns are all the same (me, you ecc), they just mistook me and you.
It's not the first time it happens. This translator mistook she and he in a previous chapter, calling Iolka a "he".
"She said I AM an idiot" not "you are". Like, come on, I will forever be grateful for translations, but at least think about the context when translating. Why would Yolka talk about her master while dying on Han's arms. Even if you don't remember that scene, it's not difficult to deduce