All Hell Breaks Loose - S3-E22
Continuity mistake: When they first bring the doctor to the manor the sisters tell him they're not sure who's trying to kill him, then a few minutes later Prue tells him exactly whose trying to kill him, Shax, the Source's assassin.
Power Outage - S3-E7
Revealing mistake: Alyssa's tattoo is visible when Phoebe leaves Cole's apartment after she fought with her sisters.
Coyote Piper - S3-E9
Other mistake: At the beginning of this episode, Tara and Kierken are arguing and Kierken says that he could always "suck you into your little mixing bottle and start again." Then Tara says that "she has a better idea," and then she stabs herself. The life essence automatically flows out of her but the knife was still in her body. Later, the possessed business man stabs himself in front of Piper and she kneels down to see if he was okay and the essence flew into her, without the knife being removed from his body. At the end, when Leo comes down after Prue stabs the possessed Piper, he kneels over her, but the essence does not flow into him. It only flows into him after he takes the knife out of her body.
Continuity mistake: When Cole gives Phoebe his card on the school campus, it disappears and reappears between shots. (00:23:25)
Revealing mistake: When Prue talks about her relationship with Justin near the beginning of the episode, she says that she finds him to be very predictable, lacking in mystery or "savoir-faire." That doesn't make sense, though, as "savoir-faire" means "know-how." She probably meant "je ne sais quoi," that is, "I know not what."
Power Outage - S3-E7
Continuity mistake: During the training drill, Piper fumbles for a knife on a table in front of her. In the shot of the table, she loses hold of the knife as she pulls her hand up, but when we cut to a long shot, it is back in her hand.
Magic Hour - S3-E2
Continuity mistake: When Piper and Prue are talking to Brooke outside, Piper's arms change from being crossed to having her hands on her hips between shots.
Sleuthing With the Enemy - S3-E8
Other mistake: When Piper puts the Belthazor flesh into the Belthazor vanquishing potion, she is the only one that gets "blasted" back even though she is the one standing farthest away from the stove and the potion.
Continuity mistake: When the trolls attacked Piper outside P3, her bag got flung into the shadows, but in the next shot, her bag was right next to her, and in the light.
The Good, the Bad and the Cursed - S3-E14
Continuity mistake: When Cole and Prue are about to shimmer to the other plain to find BO, Cole's face has not been shaved. But when they reach the other plain, his face is cleanshaven.
Continuity mistake: When Prue telekinetically moves the sin ball box across the street she moves it ALL the way across but when the man infected with greed goes to get the box, the box is only halfway across the street.
Pre-Witched - S3-E17
Continuity mistake: When Piper is sitting with Leo on the tailgate of the SUV, when shown from the front her hair is in front of her shoulder and ear, but from the back we see it tucked behind her ear. This switches constantly throughout the scene.
Continuity mistake: When Prue and Piper leave to help the hostage, Piper asks Leo, "Do you think she's mad?" Her hair is in front of her shoulders. Immediately afterwards, she sits on the couch with Leo. Her hair is behind her shoulders.
Revealing mistake: When Leo dropped the Grimlock potion, it was obviously fake when it hit the ground.
Continuity mistake: During the scene where Piper is ordering merchandise from Bloomingdale's and Prue, she and Phoebe realize the "sin balls" infected them. Piper's hair constantly changes from being in front of her shoulders and behind them.
Coyote Piper - S3-E9
Revealing mistake: After Phoebe has her premonition in the mausoleum, she wipes away the dust from the crypt to reveal Cole's father's name. Just BEFORE they show her wiping the dust away, you can see the letters in the shot of her leaning against the crypt.
We All Scream for Ice Cream - S3-E10
Continuity mistake: When the girls are saying goodbye to their father, Phoebe hugs him around the neck, then lowers her arms while they talk. When her father says "About anything," her left arm jumps back up to being around his neck, and in the next shot, it's down at the side again. (00:40:20)
Continuity mistake: When Prue is in the basement with the priest she has curly hair, but when she comes upstairs to vanquish Vinceres it is completely straight, but she definitely didn't have time to straighten it.
Other mistake: Approximately four minutes into the episode, two demons go to the manor. Pru catches them and "throws" them to the one side. Her arm motion would fling them to the right, but they fly to the left. (00:04:15)
Other mistake: At the start of the episode when Prue and Phoebe are walking down the street (just before they find the box), the person with the green jacket on (in the background) reaches into the homeless man's hat and just "scrapes" the bottom of it. Not putting any money in, or taking any money out - a completely pointless action. (00:02:05)
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.