In the "Almost Always True" number in the car, there is a bad cut when Maile's hands change position on the steering wheel and Chad's left arm goes from propped on his seatback to stretched out behind Maile.
In the pineapple field scene, only Ellie remains in the car (clearly seated in the back seat on the driver's side) while the others get out to get some pineapple at the nearby stand. Just a few moments later, Chad returns to the car to bring some pineapple to Ellie, who is now seated on the passenger side of the car, a break in continuity to facilitate the camera angle and dialogue.
When Chad first goes back to his parents' home and Ping Pong drops the hose, in one shot it is spraying water at the front tire on Chad's car. In the next shot from a different angle, it is spraying the back tire.
Every time they show the travel agency where Maile works, the traffic outside the window has a blue Ford Falcon and a 1957 white Ford convertible moving from the same spot.
A photo background of Honolulu is used during the close-ups of the picnic scene; there are waves on the shore (in the background) which do not appear to move.
Waves don't move like you see them on the beach but they are moving ever so slowly as the ocean is very far from the hill.
By the Hawaii vehicle sticker on the windshield of his car, it says the timeline is 1961. Several times in the movie it is stated that Chad had been in Europe for two full years. When Maile picks Chad up at the airport, he tells her that she took great care of his car, and her body, while he was gone. This would make the car a 1959 or earlier model. The car is actually a 1960 MGA and can still be seen at Graceland. The model year is too late for him to have had it when he departed in 1959, especially if he had it for any length of time before he left.
When Chad is playing ukulele he is not changing chords, although the music is changing.
When Chad catches up with Ellie, he brings his car to a halt on a sandy beach, but the sound is of tires on asphalt.
Chad's family home was said to be in Kahala, a neighborhood of wealthy homes next to Diamond Head. But when Chad comes to visit his parents, the silhouette of Diamond Head and the evening lights of Waikiki are visible across the water, in the distance.
Sign pointing to Waianae is actually pointing towards Manoa Valley, on the other side of the island of O'ahu.
In his nighttime car-chase after Ellie, Chad takes four arbitrary turns onto other streets which he could not possibly have known she had taken.