Continuity mistake: At the beginning of the show, when Mark and Elizabeth are playing racquetball outside, an extra wearing a top with red sleeves walks behind Mark and disappears to the left. Just then, as Mark says "Romano, he keeps stalling", we see the same extra behind Mark again, heading to the left.
Continuity mistake: While Carol is talking to Bruce's mother her hands on the railing change multiple times from hands together to arms on each other.
Answer: It was in "Chaos Theory" which is the first episode of season 9 (time code 00:13:55).
Super Grover ★