Revealing mistake: In the scene in the kitchen, Lucille Bluth takes a bottle of "Bushmills" (a brand or Irish whiskey) out of a grocery bag during a scene in the episode; however the liquid inside is clear/transparent and obviously not whiskey.
Revealing mistake: When Lucille 2 is getting a drink, the bartender goes to pour liquor from a bottle into a cup of what looks like club soda, but nothing comes out.
Chosen answer: "The One Where They Build a House," S2E2.