Revealing mistake: Right after Ignacio tells Andy and Silas to sit down with him at the diner, it's painfully obvious that the baby that Silas is carrying is a doll.
Continuity mistake: When Nancy starts her maid job at the hotel she enters a room with a wig looking around at all the mess. When the shot changes to her going to the restroom lifting the toilet lid she has no wig on, then when the shot switches back she has her wig back on.
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