Continuity mistake: In the first movie, the wedding took place on January 6th. But in the opening sequence here the framed wedding invitation says October.
Continuity mistake: Franc gives George two Vatsnik and he takes them both at the dinner table. George asks Matty to pass the rolls. Matty passes them with his right hand. When the scene zooms out and Franc, Nina, and Annie come into the dining room, Matty's left hand is on the roll basket.
Continuity mistake: In the first movie Annie had lived in the house since she was five, something significant enough that they wouldn't forget. In the second movie, George and Annie had played their first basketball game at the house when she was four.
Continuity mistake: In George's montage of memories, the girl playing Annie as a little girl looks completely different from the one playing little girl Annie in the original movie.