Little Box of Horrors - S7-E18
Continuity mistake: When Paige complains about the ringing in her ear, she's rubbing her temple with her right hand and holding a coffee mug with her left. In the next shot, which is cut too fast for her to have moved, the hand on her temple has jumped to holding the coffee mug. The mug has also jumped to in front of her mouth. (00:01:45)
Valhalley of the Dolls (2) - S6-E2
Continuity mistake: When Jason is escorting Phoebe into his office her left arm is down by her side in the rear view. When the shot changes to the front view, her left arm is across her stomach.
Revealing mistake: In the scene where Penny uses her powers at Nicholas and throws him on the dining table, it is clear that the table is a fake one simply made of simple wooden boards.
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.