Question: How is it that Stevie is so old when Nancy gets out of prison? He was an infant when she went in and she did 3 years.
Continuity mistake: When Nancy is in Doug's office, the items on his desk change position in between shots. (00:04:20)
Andy Botwin: Hey, Lupita, settle an argument for us, what do you call the thing between the dick and the asshole?
Lupita: The coffee table.
Answer: It's not uncommon for TV shows to suddenly "age up" baby/toddler characters in order for them to have more narrative purpose. Other examples of shows I can think of that did this are "Step by Step," "Last Man Standing," "Boy Meets World," and possibly "Dexter."
Phaneron ★