Episode #1.9 - S1-E9
Continuity mistake: When Ae-sin is asking Eugene to read the Korean text in her book, she places her fingers on the top of the right-hand side of the book. She then asks "Can you not read", and her fingers are now placed across both sides of the book. The shot cuts to Eugene, then back to Ae-sin where her fingers are now on top of the right hand side again. (00:48:00)