Visible crew/equipment: When Piper is coming down the stairs with the staff, if you look in the top left corner of the stairs, you can see a piece of camera equipment moving.
Love Hurts - S1-E21
Continuity mistake: Leo dies and then Piper heals him. In all future episodes it's made very clear that Leo's powers can't heal the dead.
Charrrmed! - S7-E4
Continuity mistake: Baby Chris doesn't have a binkie in his mouth, then does, then doesn't. (00:39:23)
Witch Wars - S6-E21
Plot hole: In the beginning of the episode the opening screen row Witch Wars has images of the witch Paige saved before the event actually occurred.
Which Prue Is It, Anyway? - S1-E16
Continuity mistake: When Prue goes up to cast the spell, Piper and Phoebe are downstairs and Piper's hair is down. When they hear the effects of the spell they run in to the attic and both say "Oh my god!" one after the other and Piper's hair is now slicked back in a ponytail.
Continuity mistake: When Chris and Bianca go to the manor to get Chris to go to the past, which would end up him appearing in "oh my goddess"; he's only wearing a black shirt and pants. When he arrives to the past in "oh my goddess" he's wearing a jacket, red shirt, and sunglasses. He wasn't wearing that in Chris-Crossed. And he didn't have time to change to that outfit.
The Last Temptation of Christy - S8-E15
Visible crew/equipment: At the start, Piper tells Billie she needs to be patient with Christie, and when Piper adds that if Billie needs anything they are just a call or an orb away, the pink tape mark is visible on the floor at Billie's feet. (00:01:10)
Visible crew/equipment: After orbing into the manor's attic Paige reveals to Rohtul that she switched identities with Billie, then when the real Billie walks out and joins the sisters, we can see the pink T-mark at the bottom of the screen. (00:39:35)
Visible crew/equipment: At the bank, when Nick gets off the phone after talking to his son he walks around the stanchion, and as he says, "I never wanted to hurt anybody," we can see the light green T-mark on the floor where he had been standing. (00:29:15)
Visible crew/equipment: When the smoke alarm starts blaring at the manor JD freaks out, and as he runs out of the door the reflection of a crew member wearing shorts is visible on the glass door. (00:23:05)
Continuity mistake: After Antosis and the Imp Master are vanquished, in a following shot we see Phoebe wearing a robe and sitting on the bed, then we see her "Julie Bennett" reflection in the mirror, but notice that even though the style of the robe is the same, the colorful designs are quite different in the reflection. This happens again later when the sisters and Leo are seen in the mirror's reflection, as they undo the spell to reveal their true selves. (00:33:25)
Continuity mistake: After the opening credits, while Piper tries to persuade Paige to help with the speed dating at P3, in two shots facing the bed and in the shot facing the mirror showing the "Jaime and Jo Bennett" reflection, the lamp on the far side of the bed is turned on. When Leo is holding Chris he walks past the mirror, and in this reflection that lamp on the far side of the bed is turned off, but in the next shot facing the bed that lamp is on again. (00:04:55)
Revealing mistake: While Piper is trying to convince Paige to be at P3 for speed dating, Piper says, "I will resort to whatever I have to, besides you might actually meet someone you like," and after the quick shot of Paige, when it cuts to Leo holding Chris as he's standing in the doorway asking for baby Tylenol, the mirror's glass is green at the right side of the screen - for the special effects editing of the fake reflection. (00:04:40)
Other mistake: After Piper tells Phoebe to get to know Dex well and fast because it may be the one sign Phoebe can't ignore, Piper ends the family meeting. In the following overhead shot as Piper walks out we can see her reflection in the wall mirror and it shows her long dark brown hair, but the problem is the reflection should be showing the "Jenny Bennett" golden blonde hair instead. (00:05:05)
Visible crew/equipment: While Billie is in the dorm room with her friend, Taylor, talking about the disappearances, when Taylor gets up and stands beside Billie, the pink tape mark (it's a toe box mark) is visible on Billie's seat. (00:07:20)
Something Wicca This Way Goes - S7-E22
Visible crew/equipment: When Agent Keyes enters the manor and walks into the kitchen, just as the hazmat team tells Keyes it's OK to breathe the air, the red tape mark is visible on the floor in front of Keyes' feet. (00:37:00)
Continuity mistake: After Leo rescues the driver in Texas, when it cuts to the manor Phoebe is wearing a pair of white gloves which she takes off and puts in her pocket, but when Phoebe insists she will not save another innocent until she finds out what happened to Leo, Phoebe is wearing both gloves again. (00:07:45)
Carpe Demon - S7-E14
Revealing mistake: After Leo's meeting on the bridge with two of the Elders, it cuts to Phoebe walking down the stairs as she catches Drake dancing, and when he approaches Phoebe to take her hands, the top of the set with lighting can be seen in the dining room.
Deliberate mistake: When Zankou and the Charmed Ones force the Avatars to "put the world back" by rewinding time, in the first shot of people waking up note the Jeep in the backround. The problem is the words "Jeep Liberty" are on the spare tire cover in this shot, but in the previous episode "Extreme Makeover World Edition" that spare tire cover is all black because those words were edited out in two shots. The first shot is when that group of people fall asleep, and second shot is when they all wake up the first time. (00:35:15)
Extreme Makeover: World Edition - S7-E12
Deliberate mistake: While Beta, Leo, and the sisters are walking through the sleeping city Paige notices someone in a "bad suit" moving, and as she walks over we can see a bit of the white writing on the SUV's spare tire cover, at the left side of the screen, but when Paige declares she's not paranoid that white writing has been edited out in this shot. (00:26:00)
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.