Continuity mistake: When Andy walks towards Gayle to give him the Claritin, he steps over the sign that Gayle was holding moments earlier, only for it to appear in Gayle's hand in the very next shot.
Visible crew/equipment: When Andy talks about naming the baby "Bernardo", a boom mic can be seen reflected in the glass of a cabinet to his right.
Continuity mistake: When Audra is talking to Andy outside of the clinic, everything about her cigarette changes between shots (position, smoke, etc).
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