An Apple Red as Blood - S1-E21
Continuity mistake: In Regina's dream, when she walks away from the dinner table to answer the doorbell, she is wearing black pants. When she is tied to the tree, her pants are grey. (00:01:05)
An Apple Red as Blood - S1-E21
Continuity mistake: When Regina offers Jefferson a drink, he declines by dropping the white rabbit card in the glass. In the next shot, the card is gone. (00:12:55)
An Apple Red as Blood - S1-E21
Visible crew/equipment: After Regina walks into Gold's shop and tells him about the sleeping curse, just as she asks, "Don't you understand?" we can see the green tape mark (and its reflection) on the floor in front of the display case, where Regina is about to stand. (00:38:55)
Continuity mistake: When Emma finds Snow White's glass coffin, there's a hole in the lid. In the overhead shot, the hole is rather small, but in the shot from inside the coffin, the size of the hole has changed dramatically. In the next shot, it is small again. (00:20:15)
Continuity mistake: In "That Still Small Voice", when Regina throws the piece of glass down the shaft, it lands on the rest of Snow White's glass coffin, which has several holes in it. When Emma finds the coffin in this episode, there is only a single hole in the glass, and the ends of the coffin (made of wood), are much smaller. (00:20:15)
Continuity mistake: In the scene where Mulan and Aurora are alone in the forest and Mulan is trying to make a fire, she alternates between wearing her long ponytail over one shoulder, and letting it hang down her back. (00:24:45)
Continuity mistake: After Prince Philip's body is placed on the bier, Mulan wraps the wraith's medallion in a bag and gives it to Aurora. In the wide shot, the strings on the bag are hanging over the left side of Mulan's hand. In the close-up, they are hanging down the right side. (00:33:25)
We Are Both - S2-E2
Revealing mistake: When Regina is trying to escape on horseback, as she says "Come on, Rocinante, go!", you can see that the one who's actually riding the horse is Lana Parrilla's stunt double. The stunt double's face can also be glimpsed when Regina is caught by the tree branches, and when she drops to the ground. (00:05:20)
We Are Both - S2-E2
Continuity mistake: When Regina's father, Henry, tells her about Rumplestiltskin, he refers to him as "someone Cora knew before I met her." However, "The Miller's Daughter" establishes that Cora first met Rumplestiltskin while she was locked up in King Xavier's palace, after meeting Prince Henry when she delivered the flour and at the masquerade ball. (00:10:45)
We Are Both - S2-E2
Revealing mistake: When Mary Margaret tries to escape and Mulan uses a sling to bring her down, you can see that the one who falls to the ground is Ginnifer Goodwin's stunt double. (00:39:50)
We Are Both - S2-E2
Continuity mistake: After Mary Margaret is knocked out by Mulan and falls to the ground, the amount of straws and dirt on her clothes changes between shots. When she is thrown into the dungeon with Emma, her clothes are clean. (00:39:55)
Continuity mistake: At the beginning of the episode, when Emma and Mary Margaret are walking through the camp with a group of refugees, in the first shot, they're at the edge of the camp. Cuts to a different shot, and the group have moved to a different part of the camp and are situated next to a table, before they walk over to a shed. In the next shot, they are farther away from the shed. When it cuts, they are standing next to it again. (00:05:00)
Continuity mistake: When Snow is dumped by the road by King George's men, the amount of dirt on her clothes keeps changing between shots. (00:14:15)
Continuity mistake: In the scene where Rumplestiltskin comes home and discovers that Milah is not there, the wool he's carrying keeps changing position in the basket. (00:02:10)
Continuity mistake: At Granny's, when Belle and Ruby chat, the slice of lemon and the straw in Belle's iced tea move around between different camera angles. The same thing happens to the straw in the half empty glass in front of her. (00:12:15)
Continuity mistake: Before the duel, as Rumplestiltskin says, "Sorry, but killing a man with his own sword was just too delicious to pass up", Killian's right arm is bent. In the next shot, his arm is down by his side. (00:17:25)
Revealing mistake: As Killian Jones and Rumplestiltskin duel, there is an overhead shot of them fighting, and in the next shot, you can see that Robert Carlyle and Colin O'Donoghue have been replaced by their stunt doubles. (00:17:35)
Revealing mistake: When Killian Jones is dueling Rumplestiltskin and is pushed into some barrels, you can see that the one who actually falls down is not Colin O'Donoghue, but his stunt double. (00:18:20)
Continuity mistake: When David and Rumplestiltskin are looking for Belle, when Rumple says "Look, can I ask you a question?", in the background, a man and a woman are crossing the street. In the next shot, they cross the street again. (00:20:40)
Continuity mistake: When Rumpelstiltskin and David are out looking for Belle, they cross the street, and for the rest of the scene, the pedestrians change from shot to shot. (00:20:55)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.