Continuity mistake: While Andy and Darryl are at the station talking about why Andy's been "walking around...like a zombie," Andy places a pencil behind his ear, but when it cuts to Inspector Blakely walking in behind Andy the pencil has vanished between shots, but it reappears again in the next shot. Then when Andy borrows the photograph of the knife, once again the pencil vanishes between the closeup and wideshot. (00:09:10)
Other mistake: When Andy, Phoebe and Prue are in the attic figuring out how to vanquish the ghost of Alcatraz, pages starts flipping, the book opens up to the page where the truth spell is, and Andy finds out that Prue cast that spell on him. Later when he asks how much time Prue gave him to react, she says "a minute or two". But in the episode "Truth is out there" (1-8) it was first in Prue's office when she told him, and the clock on the wall shows that it's 25 past 5. And it was 8 o'clock when Prue cast that spell. So few hours later when Andy and Prue are at Andy's door, it's almost 8 o'clock and Prue says she needs the answer now. So doesn't Andy have more like few hours rather than few minutes to react?
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.