During the performance of Love Child, Finn's plaque could be seen behind Shannon, despite Finn still being alive at the time.
The Choir Room was given to Sue for Cheerios rehearsals after losing Sectionals, however, the New Directions were still using it in this episode.
During the first Santa Land scene, Santana's hair is seen sitting behind her shoulders. However, in the next shot, her hair is in front of her without her moving it. It switches again in the next shot.
During the first scene between Kurt and Santana, when he gives her a glass of eggnog Santana is shown about to drink it or just smelling it. However, in the next shot, she doesn't have it anymore.
Cody Tolentino (Sexy Claus) invites himself to dinner at Rachel and Kurt's apartment, but he couldn't have known beforehand they shared it.
Santana says that Brittany "dumped" her, when in actuality, Santana did the breaking up.
Even though this episode was supposedly "unaired" from last season, and takes place in Christmas 2012, several characters had their season 5 hairstyles, such as Sam having long hair, and Jordan having bangs.