The Power of Three Blondes - S6-E4
Continuity mistake: The Stillman sisters strip the Charmed Ones' powers by using the same spell as Aunt Gail did in Season 2 (How to Make a Quilt out of Americans). But in that episode the Charmed Ones had to first drink a potion and Aunt Gail needed to wait a certain amount of time (at least 30 minutes) before the spell worked. In The Power of Three Blondes, the Charmed Ones never drank a potion and lost their powers before the Stillman sisters even finished the spell.
The Power of Three Blondes - S6-E4
Continuity mistake: When Phoebe kicks Mabel after the Stillman sisters have taken the Charmed Ones' powers, Jennifer Sky's stunt double's face can be plainly seen, and also her hair is darker and less full.
The Power of Three Blondes - S6-E4
Continuity mistake: During the scene when Paige goes to the citrus plant during the labor rally, her pink blouse is quite short, baring her entire midriff. When the security guard throws Paige out of the plant, Rose McGowan's stunt double is wearing a shirt in the same pink color, but it reaches all the way down to her waistline.
The Power of Three Blondes - S6-E4
Continuity mistake: When the Stilman sisters are talking about who gets which powers, Margo(the youngest)had her hand by her side, but in the next shot when she talks about Mitzy's (the middle sister) attitude, she has her hand on her shoulder.
The Power of Three Blondes - S6-E4
Continuity mistake: When Phoebe gets a phone call from Elise, Phoebe's phone changes back and forth from her right ear in the wide shots to her left ear in the closeups. (00:18:45)
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.