Na-kyum was drunk so he thought it was Sir in-hun but Seungho wanted to give up the act and asked him to call him,"my lord".
I know that, I'm referring to that panel were in chap 21 he said my lord but now he's saying my learned sir. In the raws, there isn't any change. Yoon is only remembering the convenients parts were he was addressed by his title and Nakyum being happy.
P.D. Sorry, I don't know how to explain it well, my english isn't that good.
ohh I see sorry I thought you ment something else xD
(and that's tots fine haha)
Correct if I'm wrong, but in those flashbacks of that night Nakyum should have call him "my lord" not my learned sir. Just look at chap 21 and the raws