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)
Continuity mistake: Just after Luv throws herself and K out of the car after he attempts to rescue Deckard, the two land in the water rising up against the sea wall. When Luv first kicks K, he is kneeling on the ground attempting to stand up. The shot then cuts to a different angle, where K is suddenly standing mostly upright. (02:22:20)
Continuity mistake: When Luv swims back to the sinking car, the exterior shot shows her placing her left hand on a seat in front of her. The shot then cuts to inside the car, where it is now her right hand placed on a seat that is to her right. (02:24:00)
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 swims back to the sinking car to stop Luv and rescue Deckard, K grabs Luv and pushes her up against the ceiling. There is a shot outside of the car looking inside the car, where K has his hand around her neck and is holding onto the side of her face. It then cuts to Luv where K now has his hand entirely around her neck. (02:24:10)
Continuity mistake: After stabbing K, Luv swims back to the sinking car for Deckard. Her hair is soaking wet and covered all over her fringe. When K grabs Luv by the neck, the exterior shot shows her hair parted away from the centre of the fringe. Her hair is suddenly covered over her fringe again in the next shot. (02:24:10)
Continuity mistake: When K frees Deckard from his restraints after drowning Luv, K pulls Deckard out of the water with his right hand, grabbing onto Deckard's shoulder. In the next shot, K suddenly has his right hand on the ceiling of the car. (02:25:45)
Continuity mistake: In the sinking car, when K frees Deckard from his restraints, he pulls Deckard so he is above the water. Deckard has his left hand above the water when he is pulled out, but in the next shot, his hand is suddenly below the water. (02:25:45)
Continuity mistake: When K gives Deckard the wooden horse, he tells him "all the best memories are hers" whilst looking at him, but in the next shot, K is suddenly looking at the wooden horse. (02:29:00)
Continuity mistake: When K arrives at Dr. Stelline's facility with Deckard, his left ear is visibly mangled and injured. At no other point in the movie or in any prior scene, did his ear have this damage done to it. It just appears in this scene out of nowhere. (02:29:10)
Continuity mistake: When K and Deckard are standing outside Dr. Stelline's facility, Deckard asks K "who am I to you?" and K turns his head to face Deckard. The shot cuts to K, where his head is suddenly slanted at an angle. (02:29:15)
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.