Visible crew/equipment: When Phoebe and Paige are trapped against the wall/stairs by the web, the seat that Paige rests on is visible, together with supports under her feet - also note the decorative stair baluster has been removed.
Continuity mistake: When the spider demon cocoons Piper, Paige throws a blue potion (the vanquishing potion) at her, Chris catches it and jumps over the couch, knocks Paige to the floor and Phoebe kicks Chris. The potion falls out of Chris hand and rolls into Paige's open hand, it has now turned yellow (the antidote) Paige grabs it as she stands and throws it at the spider demon again and it has now turned back into the blue potion.
Continuity mistake: When Paige is at P3, her mobile phone changes positions between shots.
Revealing mistake: When Piper is being spun in the web, she spins around and gets stuck to the wall. If you look closely Chris's eyes look above the CGI figure and do not follow it correctly.
Continuity mistake: When Chris's hand gets stuck to the first aid kit, the position of his hand changes between shots.
Crimes and Witch-Demeanors - S6-E19
Visible crew/equipment: After the opening credits, in the first shot Phoebe is at the stove, then when she turns to walk toward the Book of Shadows we can see the pink T-mark taped to the crew's black mat at the bottom of the screen, which will be where Chris stands shortly. (00:03:25)
Crimes and Witch-Demeanors - S6-E19
Audio problem: When Chris accidentally drops Phinks into the lava pit in Hell, he says "shoot", but his mouth is saying "shit." (00:21:10)
Crimes and Witch-Demeanors - S6-E19
Visible crew/equipment: After The Tribunal reverse the decision about Darryl he reappears at his desk and he hugs Sheila, then as the camera pans around to reveal The Cleaner standing in the doorway, we can see the white tape mark on the floor behind his feet. (00:39:00)
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.
A Wrong Day's Journey Into Right - S6-E20
Revealing mistake: Right after Paige is orbing out, the camera is on Phoebe and on her right, you still see Paige's shoulder. And then it cuts to Paige orbing back in.
Witch Wars - S6-E21
Continuity mistake: When Paige goes to The Bay Mirror to bring Phoebe potions we see she has 3 different colored potions: green, blue, and orange. She hands the light blue "explosive" to Phoebe, then hands the green one saying it's "acid" but when she hands Phoebe the last potion the camera angle changes and we see that she's again handing her the green one. At this time we see that Phoebe is holding the blue and the orange ones. (00:10:28)
Witch Wars - S6-E21
Visible crew/equipment: While the demons are watching Witch Wars at the bar, when the show's host, Corr, is holding an athame he tells viewers the winner will be awarded a serious power boost, then just as Corr says, "Since the shapeshifter..," in the shot of the demon bar patrons, we see the T-mark (it is not part of the Witch Wars show) taped to the floor under the table. That T-mark is visible again in at least three following shots. (00:23:35)
Witch Wars - S6-E21
Plot hole: In the beginning of the episode the opening screen row Witch Wars has images of the witch Paige saved before the event actually occurred.
It's A Bad, Bad, Bad, Bad World (1) - S6-E22
Other mistake: Isn't it amazing that both evil Paige and good Paige have the same exact rocks on their "sides" when they're fighting in the underworld?
It's A Bad, Bad, Bad, Bad World (1) - S6-E22
Other mistake: Phoebe says there's nowhere to park except blocking the neighbor's driveway. We can see in the opening shot that there is no-one parked in front of the manor, and we see spots across the street. There is also enough room to park where she is without blocking the driveway. At the end of the episode, despite not moving it and also saying that she hasn't, it's not blocking the driveway any more. The patrol guy still shoots her. It's not illegal to park there unless it's blocking the driveway.
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.