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)
The Defection of Hawkeye - S1-E8
Revealing mistake: When Clint angrily walks out on the team, the upper legs Rhodey and Julia are transparent, as the bottom frame of the security monitor behind them is visible through their aforementioned body parts. (00:09:23)