Continuity mistake: When Luv returns to the sinking car to retrieve Deckard, and K enters and grabs Luv by the neck, Deckard's hair is wet, but visibly smooth, however, in the next shot, his hair is suddenly ruffled. (02:24:10)
Continuity mistake: When K is cornered by the scavengers, he gets out of the car after they cut the door open. In the shot of one of the scavengers running up to K to attack him, nothing is hanging out of the car door. K then breaks the scavenger's back with his knee and the seat belt is suddenly hanging out of the door. (01:02:45)
Continuity mistake: When Ryan Gosling is talking to Harrison Ford not long after meeting up, Harrison Ford is wearing a grey T-shirt which has sweat stains around the neck. The sweat stains frequently grow, shrink and change shape between shots. (01:51:45)
Continuity mistake: When K shoots at Luv, she falls onto the car seat, leaving a blood splatter over it. The appearance of the blood splatter made on the seat changes between shots. (02:21:55)
Other mistake: It is established in the movie that whenever Joi is switched on through the emanator, or when she tries to communicate with K when switched off, a chorus line from the song Peter and the Wolf will play. This is shown at numerous points: when K first activates the emanator, when K is talking with Luv at Wallace Corporation, when K is talking with the hooker, when K switches her on when he is analysing the DNA, when she is reset after the car is shot down and when she switches herself on to tell the hooker to leave the apartment. However, when Luv is beating up K, Joi switches herself on to tell Luv to stop, but the chorus line from Peter and the Wolf is not heard, despite being heard every other time in the movie. (02:00:30)
Continuity mistake: When K is at Wallace Corporation, he is standing at the front desk and gives the hair sample from the replicant to the file clerk. After K hands the sample to the clerk, he rests his elbow on the desk, with his forearm placed over the edge, but in the next shot, both his elbow and forearm are resting on the desk. (00:29:50)
Continuity mistake: When K is told by Dr. Ana Stelline that his memory was real, he screams and kicks the stool he is sitting on. When this happens, Dr. Stelline's reflection can be seen in the window, with her hands at her side, but when the shot cuts to Stelline, she suddenly has one hand on her nose. (01:22:10)
Continuity mistake: When K shows Joi the emanator he got for her, he has a cigarette in his mouth in one shot, but when he opens the box in the next shot, the cigarette has suddenly gone from his mouth to his hand. (00:19:15)
Other mistake: In the trailing credits, the 2nd song, "Cloud" references the word "preformed" rather than "performed". (02:41:40)
Deliberate mistake: When Deckard wakes up in Wallace Corporation, there is a wide shot of the platform he is on. All four corners of the platform are empty in the wide shot. Deckard then looks at Wallace's visual aids as they float away, and then realises Wallace is standing in the corner directly facing where he is sitting, speaking to him. This corner was empty in the wide shot, with no sign of Wallace. Wallace could not have entered in between shots because Deckard would have seen him approaching or at the very least, heard his footsteps. This was likely done intentionally as to not give Wallace's reveal away too early. (02:08:55)
Audio problem: Just after K finds the 6 10 21 marking on Sapper Morton's tree, he begins to head back to his car. In the shot from behind K where he is first walking to the car, the only sounds heard in the shot are his footsteps and nothing else. The shot then cuts to an angle behind the car with the door opening, and it is now shown that K has set Sapper's house on fire, and the sound effects of the flames burning are suddenly heard. The sound of the flames burning the house should have still been heard in the shot where K was walking up to his car as the house was already on fire. (00:49:15)
Continuity mistake: When Dr. Stelline begins designing a memory of a birthday party, after inserting the table and birthday cake, she inserts the birthday girl, followed by two other girls standing beside her, then rotates the table to insert a third girl standing at a different corner of the table, but in the next shot, the third girl standing at the different corner is suddenly standing visibly closer to the other girls. (01:18:05)
Continuity mistake: When K is talking to Mariette at the food court, K is holding a photo in his hands. When Mariette puts her hand on K's shoulder, he is still holding the photo, but in the next shot, his hand has suddenly reached his shoulder, trying to move her hand. (00:44:50)
Continuity mistake: When K is fighting off the scavengers in the scrap yard, he shoots at a few and keeps his gun pointed at them. When he says "stay back", he has his gun pointed forwards in one shot, then pointed to the right in the following shot. (01:02:55)
Continuity mistake: When Joi projects a holographic version of the wooden horse from K's memory, she flips it over revealing the date on the bottom, but when K goes to lower her hand, the horse is suddenly face up again. (00:56:25)
Continuity mistake: After K destroys the two other cars, Luv runs up to the front of the car to see out the front window. She places her left hand on the driver seat, with her hand touching near the bottom of a metal plate attached to the side of the seat. The shot cuts to a different angle, where he hand is now touching most of the metal plate attached to the seat. (02:20:05)
Continuity mistake: At Wallace Corporation, when K is walking through the data vault, the clerk stops to open the drawer with the replicant serial number, standing in front of it, but in the next shot, he is suddenly standing beside the open drawer. (00:31:25)
Continuity mistake: When the police are examining the bones found in Sapper Morton's locker, when Nandez says "The Soyuz samples indicate she's been buried for thirty years", the shot is focusing on the table with the bones on it. A doctor is examining one of the bones in the background, but in the next shot, he is suddenly holding something with his hands raised away from the table. (00:24:05)
Continuity mistake: When K and Deckard realise that Wallace's thugs have reached them, K picks up a pair of binoculars and looks out to see. The binoculars have a strap extending from them at first, but from another angle, the strap is no longer visible. (01:58:05)
Continuity mistake: When Luv walks over to Wallace to with a box of devices to access his visual aids, Wallace places his left hand on the top of his leg. Luv then slides open the box, and Wallace now has his left hand closer to his knee. (00:39:30)
Answer: Think of any manufacturing process. Samples of new products are frequently created and then immediately destroyed. Also, the new replicant would require processing, training, etc. It was simpler for him to just dispose of the test.