The Day The Magic Died - S5-E15
Plot hole: In the episode "The Day Magic Died," Phoebe and Paige first find out that magic is down when Paige tries to orb the unicorn. But, when she tries to orb it, she makes a scrunched up face that would suggest that she knew magic was out and she hoped that she could orb.
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.