You Could Drive a Person Crazy - S2-E2
Continuity mistake: When Gabby first goes to visit Carlos in prison, they sit down at a table. Watch Gabby's arms. At one point, she folds her arms, yet in the next shot they are on the table. In the next shot they are folded, and in the one after that they are back on the table.
You Could Drive a Person Crazy - S2-E2
Continuity mistake: When Bree is at the shop and people are waiting behind her mother-in-law, you can see how the first woman gets into the shop but you cannot see the man who came in, he just suddenly appears there.
You Could Drive a Person Crazy - S2-E2
Continuity mistake: When Susan is screaming at Edie and she's going away, Susan's hands change position between shots.
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.