Revelations - S5-E22
Revealing mistake: Just before Teal'c and O'Neill get to the engine room door, Carter can be seen hiding around the corner. (00:27:40)
Revealing mistake: The footage of Monkey Bulk doing flips is just one backflip forwarded and reversed several times - as evident by the movements of the people behind them.
Super Nova - S1-E2
Revealing mistake: When Stan, Xev and Kai are walking to the Memory Chamber, they seem to walk out of a two dimensional line at the lower left into the scene. The set and green screen weren't quite synched.