There's No Place Like Home (2) - S5-E6
Other mistake: At the very end, Mr. Hanson is seen walking toward the church. Because of his stroke, he's slow and unsteady. We see several close-ups of his feet, showing how he's struggling. Two of those shots are the same footage. It's obvious, because you see that he drags his foot over a small stick in the road and stumbles - and in both shots, it is exactly the same.
Backlash of the Hunter - S1-E1
Other mistake: The bad guy collapses after drinking what Sara gave him, but in the close-up she managed to squeeze barely 1 drop of the substance and it went right on top of the horizontal ice cube. It must be the most powerful narcotic in the world, putting KO a mountain of a man within seconds with a single drop that arguably didn't even mix with the drink. Had she put a couple drops in, it would have straight up murdered him, then.
Just a Matter of Time - S5-E13
Other mistake: In reality, Steve would radio in from the capsule as soon as he woke up on Earth, but strangely failed to do so until later in the episode.