Continuity mistake: When Bree is about to leave the hospital she picks her bag up with her left hand to put it on her right shoulder but when the camera angle changes she's put the bag on her left shoulder with her right arm.
There Is No Other Way - S2-E16
Continuity mistake: In "Thank You So Much" Valentine's day was on a Saturday or Sunday. In this episode, They are showing Bree marking her chores off a calendar for February and March 2006. The calendar matches the real calendar and Valentine's day was a Tuesday this year. The calendar doesn't match their previous episode. And they do state that "today is Valentine's day." not that they are celebrating it on the weekend.
Continuity mistake: As Chuck is speaking to Ben, the amount of sunlight on the lamppost behind Chuck keeps changing between shots.
Continuity mistake: In the 1994 flashback where Bree introduces herself to Mary Alice and forces her son Andrew to apologise when he stole a ornamental garden frog, the position of the frog changes between shots as Bree hands it to Mary Alice.
Deliberate mistake: When Susan falls through the floorboards of Mike's house she uses the nearby towel to try and get the dog Bongo to help her. If you watch at the different angles the position of the dog keeps changing. When it shows Susan from behind the dog is almost right next to her face and stepping on the towel. In the shots from in front of Susan the dog is nowhere near the towel or even in the shot. This mistake looks more deliberate as the front on shots of Susan, the dog would likely have blocked her face from the camera.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: When Lynette is chasing her neighbor out of her boys' bedroom and has a pillow in each hand, one is spotted and one is light blue. She raises the light blue pillow to throw at the neighbor. When the camera switches to the bedroom door, its the spotted pillow that hits the door behind the fleeing neighbor.
Continuity mistake: Susan's house is burned down by Edie towards the end of season 2, but at the beginning of season 3 the house is exactly as is back to normal and as it was before the fire.
Like It Was - S3-E4
Continuity mistake: When Bree is talking to Vera about Andrew and her husband, Vera is holding a nearly empty glass of tea. She then fills the glass to the top, but when she picks up the glass after doing so, it's nearly empty again.
Like It Was - S3-E4
Continuity mistake: When Bree goes round to visit Vera, the camera is reflected in the door as Vera opens it.
Sweetheart, I Have to Confess - S3-E6
Visible crew/equipment: When Susan starts talking to Ian after trying to hide from him, a boom mic and pole are reflected in the rear window of her car for a few seconds as the camera pans over it.
Visible crew/equipment: When Karen McCluskey was stepping from the car when she was taking Bree Van de Kamp to the hospital the crew members appear in the mirror.
Secrets That I Never Want to Know - S8-E1
Character mistake: When Gabby and Bree go to move Gabby's stepfather's car, they realise his car is a stick shift and Gabby says that she has driven a stick shift only once in high school. This is incorrect, as in season 7 episode 8, Gabby has to drive Hector's car home, which was also a stick.
Factual error: When Gabrielle becomes a widow she marries Carlos again in front of a priest. But the Catholic Church doesn't admit divorce, so in their eyes Gabrielle and Carlos were still married. They should have repeated a civil wedding, since only the civil effects of marriage were ended with their divorce.
Audio problem: When Gaby goes to introduce Angie to Heidi Klum at the fashion agency, Gaby goes up to Heidi and says "It's me, Gaby." When the camera angle changes to behind Gaby in the next shot, she is saying the same thing again, but no words are coming out.
Other mistake: When Lynette and Tom are waiting for their kids at the bus stop, the bus that drops off their boys says "Briarcliff Academy." The boys actually go to Barcliff Academy.
Continuity mistake: Carlos swiped every thing from the table but a fork appears behind Edie. (00:18:35)
Nice Is Different Than Good - S6-E1
Continuity mistake: At the end of season 5, Lynette finds out she's about 6 weeks pregnant. At the end of the same episode, they do a "Two Months Later." In Season 6, Episode 1, Tom says after an argument with Lynette "Only 8 and a half more months." Lynette should be in her second trimester by then, with at most 6 months to go.
What Would We Do Without You? - S3-E22
Revealing mistake: When Lynette tears open Tom's shirt before making love to him, you can see there are already scratches on his chest before she scratches him.
My Heart Belongs To Daddy - S2-E4
Continuity mistake: When we see Danielle standing with Bree in the kitchen, you can see a long wall behind Danielle without a passageway. But when the shot changes to Andrew and George, Danielle is standing in the background.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: When Gabrielle fires Yao Lin, you can see that Yao Lin isn't wearing long sleeves, but when she passes Gabrielle, you can see that she's wearing a long sleeved white cardigan in the reflection of the mirror behind Gabrielle.
Answer: Kayla was sent away in episode 16 (The Gun Song) in season 4, after falsely accusing Lynette of child abuse. She now lives with her grandparents - probably Nora's parents.
I'm curious why we never see her again, why she never talked about, and why Tom never mentions visiting her.