Tabula Rasa - S6-E8
Continuity mistake: In the beginning of the show, Buffy has two necklaces on, one long and one short. However, when Buffy, as Joan, is telling everyone her plan to get away from the vampires, she only has the short necklace on. Then when she is outside, running from Spike, as Randy, both necklaces are back on.
Revealing mistake: When Buffy is at the desk of the social assistant you can see the white wire at the left of the keyboard. The white wire controls the fake keyboard: you can see the wire moving. (00:20:50)
Continuity mistake: When Willow is outside the jail just before she starts pulling bricks out, there are two policemen walking past the open door, but a split-second later as the shot moves out to look up at the window, they disappear.
Visible crew/equipment: Just after Dawn says "I like the trailers", we fade to black/commercials, then up again. Keep a close eye on the left side of the screen - you can see what looks like someone's hand flash into frame for a second, despite Dawn being alone in the room - looks like the director's hand signalling action. (00:25:50)
Revealing mistake: After the demon throws Buffy into a wall, she crashes to the ground. As she backs away, you can see the blue crash mat she landed on in the bottom left of the screen. (00:33:55)
Once More, With Feeling - S6-E7
Continuity mistake: During the final song, everyone, including Spike, sings "When Does the End Appear?", however, one shot later, Spike is seen starting to sing the word "appear" again and then he stops.
Continuity mistake: When Spike is looking out the window at the demons rampaging in the street outside Buffy's house, Dawn can be standing behind him with her hair trailing down below her breasts. In the next shot, when Spike pulls her away from the window, her hair is pulled back behind her shoulders despite her not having moved. (00:53:10)
Continuity mistake: In 'Flooded', Jonathon reads a few things off the board listing the Trio's ultimate aims. One of the things he reads out is "prototype jet-packs that actually fly", but when the list is shown a few seconds later jet packs aren't mentioned on it. (00:27:10)
Continuity mistake: The security tag on Buffy's new jacket shifts when Buffy first sees it. (00:12:50)
Continuity mistake: Buffy's shoes change from being nice shoes, to runners (e.g. When Buffy climbed out of her grave, she had nice shoes, but when she jumped over the fence, she had runners on).
Continuity mistake: In the basement, immediately after Buffy pulls her hand out of the demon's chest, her fist is completely dry. Two shots later, it is covered in gooey demon fluid. (00:40:35)
Continuity mistake: Timothy is wearing disposable gloves as he is training Buffy at the grill, but in the shot when he puts the raw patties on the grill, he is barehanded. (00:16:15)
Continuity mistake: After the 'hell hogs' interrupt the ritual, Xander pulls Willow out of the way. He then tells Anya and Tara to "take off." which they appear to do, starting to run Into The Woods. But then in the next shot, they are back standing still in the clearing (on the left of the shot).
Seeing Red - S6-E19
Continuity mistake: At the beginning of the episode, Buffy is running from the large saws and jumps out the door, she sits up and you can see the book is fully intact and in one piece. After the opening credits Tara picks up the same book and it falls apart from being cut in half.
Once More, With Feeling - S6-E7
Audio problem: During Buffy's first song she does a spinning kick to a vampire's face as she sings, "I've been making shows of trading blows, just hoping no one knows." But as she spins, her lips are not moving.
Visible crew/equipment: When Buffy and Dawn are at the top of the metal tower, and Buffy is still very dazed from being called back, there is an overhead shot with a piece of the tower falling down; if you look left of the falling piece, you can see a guy wearing a hard hat walking about.
Once More, With Feeling - S6-E7
Visible crew/equipment: When Buffy kicks the front door of The Bronze down to confront Sweet and save Dawn, a cable can be seen attached to the door used to pull it down.
Seeing Red - S6-E19
Visible crew/equipment: When Buffy says, "Goodnight, bitch" to Warren, right before she kicks him it is quite obvious that it is his stunt double.
Audio problem: When Warren, Jonathan and Andrew break into the museum to get the diamond, Warren makes a hole in the glass, then pushes it through, but when it lands, it sounds like plastic, not glass.
Chosen answer: He had larangitis and because of the shooting specifications they had to have him shoot the scene with a bad throat, they then re-recorded his lines and dubbed them. At various points during the scene and indeed the episode you can see him touch his throat or rub it.