Revealing mistake: Hannah sits in a conference room and pulls a landline phone towards her to dial her friend, asking about the will Owen left. The phone however isn't in any way connected, hence no call could have taken place.
Chips Ahoy - S2-E10
Revealing mistake: Flobert comes into the court carrying a bag of potatoes which would probably weigh 80 pounds. It must be a rather inaccurate prop because it moves like it only weighs about 15 pounds.