Sense and Sense Ability - S5-E20
Continuity mistake: During the meeting with Phoebe's boss (regarding her newspaper column), when Phoebe's hearing is "stolen", the white handbag flips over (top faces Phoebe, then bottom) and upside-down (note flap/clasp) on the desk between shots.
House Call - S5-E13
Continuity mistake: When Leo finds Piper on the ladder removing the "filthy" wood shingles he's wearing a crew-neck grey and blue pullover, but when Piper climbs off the ladder and Leo tells her she needs to snap out of it Leo is wearing something beige with a collar, then it's back to the crew-neck pullover. (00:31:00)
Continuity mistake: Whilst Paige and Phoebe are jumping through time, they witness Piper telling Leo she loves him for the first time. After she tells him, Leo orbs Piper and himself away. This doesn't make sense as the first time Leo orbs Piper is in season 2 Episode 8 - the water demon episode - which is actually further on in time from when she tells him she loves him (which is from season 1 episode 21).
Continuity mistake: In the teaser Piper is reading a fairytale book to her unborn child. When Paige walks in we get a glimpse of the book, and both pages are filled with words. When Paige walks out and we see the book again, the right page of the book has a picture on it. (00:00:15 - 00:01:35)
The Importance of Being Phoebe - S5-E11
Continuity mistake: When Kaia, pretending to be Phoebe, holds up the document from the bail bondsman, it jumps from her left hand to her right. (00:33:20)
Sense and Sense Ability - S5-E20
Continuity mistake: When Phoebe loses her hearing during her meeting at the newspaper, she holds her hand up to her ear while talking to Elise. In the next shot, her arm is suddenly resting on the tabletop, with no time for her to have moved it. (00:12:45)
Continuity mistake: Right after the Hawker demon attacks, Piper picks the baby up and the head of the doll is covered and you can't see the face; a quick change in camera angles shows the baby's face and the blankets are all arranged and folded to frame the baby and no time has elapsed to allow this to happen. Also, the doll used as the baby double is much smaller than the baby and is very noticeable in shots that switch back and forth between the covered doll and real baby.
Continuity mistake: When Phoebe is talking to Elise on the phone, the phone handset jumps from Phoebe's left hand to her right hand, then back to her left. (00:20:40)
Continuity mistake: In the opening scene in the club with the DJ playing, they have an overhead shot of the club. In the lower right hand corner we see Paige and Dave talking with Leo and Piper, but after the scene cuts out Piper is just walking in. This can't be since we already saw them talking.
Continuity mistake: When Paige goes to Cole for help saving Phoebe, she puts her hand on his chest. In the next shot, her hand disappears, with no time for her to have moved it. (01:11:35)
House Call - S5-E13
Continuity mistake: When Jessica approaches Paige and Glen in the church, she puts her hands on her hips. When the shot cuts to Glen and back, Jessica's arms are crossed over her chest. (00:21:30)
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.