Most Hooreng's Ahri and Leblanc's comics revolves around Ahri trying to play tricks on Leblanc and she punishes Ahri most of the time because of it.

Just changed some of the translations:

무슨 심경의 변화인지는 모르겠지만... -> I don't know why you've changed your mind...

심경의 변화 literally means change of heart/mind/emotion/etc. Physical transformation, on the other hand, usually translates into 변신.

More literal translation would have been something along the lines of "I don't know what's with the change of heart..." but tought that would be awkward. I was tempted to do something like "I don't know you're (suddenly) acting like this/behaving yourself," but decided to keep it closer to the original.

조용히 있으니 한결낫군 -> It's a little better now that you're quiet...

The original line doesn't mention anything about Ahri being cute. I'm just worried about "little" since 한결 means much/more; I thought "much better" would have made Le Blanc sound tired of Ahri, so decided to go with little instead...

It will be good if someone can come up with something more fluent.