Blast from the Past/Chew Said a Mouthful/See What Develops - S1-E8
Continuity mistake: See What Develops: When Lumpy enters the office near the start, there is only a bulletin board on the right of the elevator and a clock on the left of it. A moment later, elevator buttons have appeared between the elevator and the bulletin board, another bulletin board has appeared to the left of the elevator, and the time on the clock changes. This all reverts in a following shot. (00:15:06)