Continuity mistake: Charlie, Olivia's former partner and friend in the FBI shows up in this episode during the interview with Mrs. Rusk, but Charlie was killed off by one of the shapeshifters in a previous episode, and the shapeshifter that killed Charlie was himself killed off by Olivia, who in other episodes reflected back on killing him. This episode was supposedly meant to be in season 1 as ep 21 or 22. Unknown why they didn't air it then, and decided to put it in the middle of season 2 (for no apparent reason).
Continuity mistake: All shots of the Jeep Cherokee prior to it crashing (and during the process of flipping over) show that it wears factory-optional silver steel wheels of a 'star' style. But as the wreck settles upside-down, it's wearing plain steel wheels (like those found under full wheel covers or on a spare tire).
Continuity mistake: Rex's kama (the black kilt-like thing he wears) is missing twice: first when he, Anakin and Ahsoka are looking at a hologram of an AT-TE on the Resolute's bridge, and second when Anakin's trap for Grievous is revealed, and Rex orders the AT-TEs on the asteroids to fire. (00:01:12 - 00:04:10)
Continuity mistake: During "Brand New Day", at one point, Dr. Horrible stabs a picture of Captain Hammer attached to a dartboard with a handful of darts, all right in the center of the picture. A few shots later as Dr. Horrible sits, suddenly the darts are far-more spread out. (It's in the background and can be hard to see, but it's noticeable.)
Triumvirate of Terror! - S3-E8
Continuity mistake: Back at their kingdom, Wonder Woman and her mom are sitting and talking as they watch the fighting before them. The mother turns her head towards Wonder Woman in a close up and says "Oh please. It's just one little contest." It then changes to a wide shot again and suddenly her mom is looking straight forward. (00:10:45)
Continuity mistake: When the team is checking out the grocery store in Piedmont, they exit the building and a Humvee is in the middle of the street where there was no vehicle before. They had driven that Humvee but had parked it elsewhere.
Continuity mistake: When Wolverine opens the door as Emma Frost is there, he is standing roughly two steps away from her. When he asks her why she's there, he takes a couple steps towards her and still only manages to be roughly the same distance away from her as he started. (00:02:17)
Containment - S1-E5
Continuity mistake: At the end of the episode, when the bad guy is preparing the syringe of small pox, he follows the usual method of tapping out any air in the tube - when he is shown injecting himself, a large air bubble is back in the syringe (which would probably kill him quicker than the smallpox).
Bloodshed in the Bordello - S20-E12
Continuity mistake: Zac goes in a playroom to investigate, puts a truck on a playhouse roof and tries to get a presence to push it off but nothing happens. He walks around to investigate the rest of the room. He squats down to look inside of a tent and when he does the camera pans out to show Billy in the doorway. When it does the truck is not on the roof of the playhouse, but when Zac stands up and walks by the playhouse, the truck comes flying off it.