Crimes and Witch-Demeanors - S6-E19
Other mistake: At the end, it shows the Charmed Ones orbing out of the trial, but Chris and Leo never leave. Right after the Charmed Ones orb out, Barbas begins discussing his evil plans with Gideon, so wouldn't Leo and Chris find out that Gideon is plotting against them? After they talk, the camera pans out and Chris and Leo are not there. I guess they just forgot to put in the scene where they leave.
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.