And the Sea Shall Give Up Its Dead - S1-E1
Revealing mistake: When Tony Stark is trying to figure out why the Mandarin called off his goons after attacking him by the submarine, the computer monitor and the desk tilt slightly, likely indicating a composite shot.
Life Lessons - S1-E4
Revealing mistake: When Danziger and True are pursuing Gaal, they drive up next to Gaal and his horse. In several shots it's obvious it isn't Danziger driving, but a stunt double. (00:47:10)