Character starts running twice because of editing mistake in the end of movie.
During Elvis's romantic boat ride with Dolores Hart both the moon and Elvis's position shift from shot to shot.
Throughout most of the scene near the end of the film, in which the injured Danny recovers consciousness in Ronnie's cabin, his slashed arm is seen to be tightly bandaged - presumably Ronnie's first-aid handiwork. However, in one shot, the bandages are hanging loosely from his arm.
When Elvis in on the sidewalk talking to Ronnie who's sitting in the car, and the camera is on Elvis, Ronnie is yards away from any windshield or dashboard of the car, yet when the camera is on Ronnie, she's inches away from the front of the car.
In the beginning of the movie there is a scene where people on the street sing a song. In one part a woman is singing on the song, but the picture shows a male singer.