Other mistake: In both scenes in which Phoebe's hair is cut, her hair is up, with very little loose hair. There is no way that the amount of hair shown to be cut in both scenes could have come from her head. In the first scene, it is very clear when the demon cuts her hair, it is a few tendrils, yet when he is shown with Imara, it is a very measurable amount of hair. The super speedy guy who cut her hair the 2nd time, when she was Imara, was too quick to see the actual amount cut, but again, because of her hairstyle, he could not have cut the amount he shows to the Charmed Ones in the next scene.
Continuity mistake: When Paige is complaining to Leo about not having time to take on a charge as a Whitelighter, she rests her head in both of her hands on the kitchen table. In the next shot, her head is only resting on her right hand. (00:00:30)
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.