Visible crew/equipment: Right before Bree drives herself to the emergency room and is talking to Mrs. McCluskey, a crew member's face is reflected in the car's left wing mirror.
Character mistake: When Bree calls the police when she hears a noise downstairs, she says she lives at 4355 Wisteria Lane when her address is in fact 4354 Wisteria Lane. 4355 is the Scavo residence, not the Van De Kamp residence.
Continuity mistake: As Chuck is speaking to Ben, the amount of sunlight on the lamppost behind Chuck keeps changing between shots.
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.
Continuity mistake: When Lynette asks Jane to not steal Tom from her, the door behind Lynette goes from being open ajar to fully closed between shots.
Secrets That I Never Want to Know - S8-E1
Continuity mistake: When Gaby looks for her stepfather's car with Bree, Chuck takes over and drives it for them. But in past episodes the stepfather's Ford Focus was a two door model not a four door.
Continuity mistake: Lynette is giving a speech during Renee's wedding. In some shots, she holds the microphone in her right hand and a glass of wine in her left hand. In other shots, she holds the microphone in her left hand and a glass of wine in her right hand. (00:32:40)
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.