Audio problem: Marta is on the stairs confiding in Michael. At one point the camera angle switches and we hear her say "commitment" but her lips are still. (00:10:15)
Continuity mistake: When Michael is sorting through the pile of mail, just before the doorbell rings, we see him place the same green envelope on the table twice.
Continuity mistake: Just after Gob snatches Michael's sandwich away, Michael is left with just a few torn pieces of napkin. Seconds later he has what appears to be a whole napkin in his hand again.
Continuity mistake: When the two Lucilles are talking at the bar, the position of Lucille Bluth's drink on the bar changes between shots.
Continuity mistake: When Michael and Marta are talking in the doorway at the hospital, the position of Marta's handbag straps changes between shots. Sometimes both straps sit over her shoulder, whilst in other shots one strap is slipping down her arm.
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.