Continuity mistake: In the scene when Phoebe and Leo return to the rest home, after she has changed places with old Phoebe, when Antoine places the amulet on her, he doesn't clasp it behind her neck, he just lays it on her. When she sits up, it doesn't fall off.
Continuity mistake: The family tree shows that Grams died in 1968 but the sisters were all born in the1970's. Didn't Grams raise the girls after Patty died in 1978?
Continuity mistake: Leo says that Piper's past lover is his past life. If it was a past life, in 1924, that means Leo must have died almost straight away to be old enough to qualify as a doctor in WW2. And it wouldn't be his past life but his own past if it was the same life from before he became a Whitelighter. But then he'd also have been 15-20 years older before he died in WW2.
Continuity mistake: When Piper confronts Phoebe about casting the spell to help her decide between Dan and Leo, Phoebe's finger jumps to the back of her ear, then disappears. In a following shot, her finger is now resting on her neck. (00:09:45)
Continuity mistake: When Prue shows her sisters the article in 415 Magazine with her photo credit, in the closeup we see that Prue opens the magazine with the article and Maggie's photograph on the page to the right, but in the next shot facing Piper and Phoebe the magazine is folded open and they're looking at the page to the left with an entirely different page to the right. (00:40:40)
Continuity mistake: In the shot where Leo gets his wings back, his eyes are brown, usually they are blue.
Chick Flick - S2-E18
Continuity mistake: After Phoebe kisses Billy, she sees that the makeup over his lips has washed off and that they're in black and white again. While she applies more to him, the phone rings, Billy turns his head, and his lips are normal. In the next shot, they're back to being in black and white. (00:22:15)
Chick Flick - S2-E18
Continuity mistake: In the teaser, Phoebe took off her messenger bag while she was sitting in the chair talking to Prue, and she left it there when she went up to get the door. For the rest of the scene at the house, including when Phoebe and Prue ran out of the door, Phoebe was not wearing the bag. Then, when we saw them outside immediately thereafter, Phoebe was wearing the bag again.
Continuity mistake: After the ghost chases Gibbs out of his pawn shop, and the police arrest him, his shirt goes from being on fully to half-off between shots (particularly noticeable when Tyra's father tells him to burn in hell).
Continuity mistake: Near the end of the episode Piper is talking to her sisters in the parlor with her watch is on her left wrist and a bracelet on her right wrist. She goes upstairs to her room to cry and her bracelet and watch have switched places. (00:39:05 - 00:40:00)
Be Careful What You Witch For - S2-E22
Continuity mistake: When Piper and Leo confront the genie at the restaurant, the genie is eating food as fast as he can. At one point he gets a line of pasta sauce on his cheek. The shot changes, then goes right back to him only now the sauce is gone with no time for him to have wiped it off, especially since his hands are full of food.
Be Careful What You Witch For - S2-E22
Continuity mistake: When Phoebe and Piper are leaving to go get Prue, Piper kisses Leo on the cheek and there is a lipstick mark on his cheek. Then the shot goes to Piper then back to Leo, and the mark has gone with no time for him to remove it.
Be Careful What You Witch For - S2-E22
Continuity mistake: At the end of the episode, when Prue shuts the door magically it shows the inside of the house. There should be a doorway parallel to the front door that leads from the foyer into the dining room, but instead there is a wall.
Be Careful What You Witch For - S2-E22
Continuity mistake: When Piper and Leo find the genie at the restaurant, look at the girl in the background, when Piper freezes the time, first she's talking to someone, then she's looking at a menu.
Continuity mistake: When the Charmed Ones' father, Victor, came to San Francisco in episode 1-3: "Thank You for Not Morphing," his last name was Halliwell. But when he came back in the third season and later, his last name was Bennett.
Continuity mistake: When Cole catches Phoebe's karate kick at her school, her foot is up near Cole's shoulder, but then moves down much lower. (00:18:20)
Continuity mistake: In the scene where Cole has caught Phoebe's karate kick at school, Phoebe's hands are both clutching her school books. In the following shot, her left arm is in a completely different position, and there's no reason for her to have moved it. (00:18:25)
Continuity mistake: When Cole gives Phoebe his card on the school campus, it disappears and reappears between shots. (00:23:25)
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.