Buffy The Vampire Slayer (1997)

Goodbye Iowa - S4-E14

Visible crew/equipment: When Buffy and Riley are talking at the crime scene, where he tells her about Maggie Walsh's death, one of the camera shots has a very visible black border around the entire edge of the screen as if the lens shade was visible in front of the lens and could be seen in the shot. (00:18:20 - 00:19:40)

A New Man - S4-E12

Revealing mistake: In the scene where Giles is dusting his book shelf he takes a book from the shelf and reads from it, you can see that the pages have nothing written on them. (00:07:30)

bic

The Initiative - S4-E7

Visible crew/equipment: In the scene where Spike escapes from The Initiative a black curtain can be seen to the right of the screen after the other vampire is release from his cell. The curtain serves no purpose to the set or scene and it disappears in the next shot. (00:13:25)

bic

Beer Bad - S4-E5

Visible crew/equipment: When Buffy, Xander and Willow get up from the table, the personal microphone equipment clipped to the waistband at the back of Xander's pants is visible; he adjusts his shirt to cover it as they turn to walk.

THGhost

The Freshman - S4-E1

Continuity mistake: When Buffy is talking to Giles after his run, his towel moves from being on one shoulder to being across his back and over the other shoulder to being back on one shoulder.

tracey jones

Where The Wild Things Are - S4-E18

Visible crew/equipment: In the scene where Xander and Anya make the last attempt to rescue Buffy and Riley, Anya is attacked by some vines and you can see another set of hands from the crew pushing the vine towards her.

vocalbeauty

Where The Wild Things Are - S4-E18

Visible crew/equipment: Toward the end of the episode Giles, Tara and Willow contact the spirits. Just after the spirits vanish, in the bottom left corner of the screen a crew member's leg is visible.

Invisible Stalker

Hush - S4-E10

Continuity mistake: Near the end, when Spike takes the cup of blood from the fridge, we can see that it is full to within a 1/4 inch of the rim. However, when the shot changes and he drinks it, he tips the cup almost 45 degrees before putting his lips to the cup and drinking. If the cup had been as full as previously shown, the blood would have begun pouring out long before Spike ever drank form it.

Guy

Wild At Heart - S4-E6

Revealing mistake: In the scene when Oz stops the female wolf from attacking Willow, and they both change and Oz tears her neck out, if you look closely, you can see the actor's real skin at the neck.

Restless - S4-E22

Continuity mistake: In Willow's dream when she's painting symbols of Tara, in the shot where she draws the last symbol, she hasn't finished the line, but in the next shot, she had finished that line.