Episode #1.4 - S1-E4
Continuity mistake: When Weol-ju and the old lady are having a drink outside the supermarket, in the shot where she says "It seems like your parents raised you well", the position of her fingers change on the plastic cup she is holding when it cuts between different angles. In one shot, her fingers are placed along the side, but in the shot after, one finger is placed on the lid, then all fingers are placed on the side again. (00:09:35)