Continuity mistake: Chunk is tied to a chair when Jake and Francis leave him in the room with Sloth. When Chunk introduces himself to Sloth, the rope around Chunk's right shoulder has gone up, off the chair, but then manages to lower itself again, back over the chair in following shots. (01:04:05)
Continuity mistake: At the end, when the Fratellis show up on the beach, Chunk and the others run over to Sloth to protect him and Chunk stands on a large boulder. The ground is rocky and the sand is brownish. When Chunk tells Sloth that he'll live with him, in the overhead close-up Chunk is now shorter than Sloth and the ground is pristine off-white sand. (01:44:10)
Audio problem: In the cave at the start of their trek, when we hear Andy say, "We've been walking forever. How much further do you plan on going?", her mouth is not in sync at all with those words. (00:47:40)
Continuity mistake: When Data is being dragged by the sticky dart in the opening sequence, the camera angle changes from in front to behind, and suddenly the distance between Data and the oil drum dramatically increases even though he is moving towards it.
Continuity mistake: When Sloth is trying to reach for the Baby Ruth, the candy bar's position and the way it faces changes between shots.
Character mistake: When looking at the newspaper about Chester Copperpot, the caption under his picture reads, "Reclusive scavenger claims, 'I have they key.'" It should read "I have the key."
Continuity mistake: When the Goonies are standing behind the waterfall in the cave underneath the wishing well, they've got dry hair. But just before Mikey walks through the waterfall, you can see that his hair is soaking wet already.
Revealing mistake: When Stef blindsides Mama Fratelli with a punch to the face, you can see Mama Fratelli reach up and grab her face before the punch lands. (01:34:30)
Other mistake: When Mikey is telling the story of One-Eyed Willy, something stuck to the lens of the camera is visible on his head. This is visible on the television airings but may or may not have been fixed for home media.
Revealing mistake: When Mikey is on the balcony he turns towards Bran to hug him, and then Bran carries Mikey all the way to back of the balcony. During that whole time there are leaves falling from the sky. All the trees are outside of their picket fence and lower than their balcony roof. So they must have had crew on the roof throwing leaves down for the effect. (00:21:10 - 00:21:40)
Continuity mistake: When Sloth kisses Chunk for sharing his chocolate, Chunk's cheek swaps from dirty to clean between shots.
Continuity mistake: Before Chunk opens the Fratellis's door, Data looks at Mouth, and then turns his head at Chunk while smiling. A frame later, from a new angle, he is still looking at Chunk and repeating the previous movements.
Continuity mistake: When Jake Fratelli is in jail, the position of the sign on his chest changes between the first and second shot. The right tip is first touching his chin, and a frame later it's 15 cm below.
Continuity mistake: When the cop is reading Jake's suicide note the distance between one side of the scarf and the other keeps changing between shots.
Continuity mistake: When Data is about to slide through a cable to enter the house, the sky swaps from bright blue coloured in the close-ups to yellowish early dawn type in the wide angles.
Continuity mistake: During the initial chase, the way Data's sweatshirt folds over his utility belt keeps changing through shots.
Continuity mistake: When the boys run out on Brand and Mouth flattens his tires, Mikey is wearing a denim jacket. When they are looking for the restaurant after riding their bikes, he is wearing a yellow coat over his denim jacket he didn't have with him when he left the house. Mouth also suddenly has a raincoat over his jacket.
Continuity mistake: When Chunk kicks over the frame with Chestor Copperpot, it then shows his arm picking up the frame. The arm/hand shown in the close-up is an adult's, which is older-looking and hairier than Chunk's very young, chubby arm/hand.
Factual error: There are a few problems with the suction cup that Data shot onto the metal drum. First off, suction cups don't stick to curved surfaces. Second, dirt and grime, which the drum obviously had, would not allow a suction cup to stick. In any case, it shouldn't have stuck.
Factual error: When the Fratellis break Jake out of jail, Francis shoots a trail of gasoline on the ground with his pistol, which lights it. In reality, this wouldn't happen, more than likely the bullet would bounce of the ground or embed itself, but not cause any sparks (if it caused any, wouldn't be long or hot enough to ignite) to light the gas.
Answer: According to Mikey and Mr. Walsh, one of his crewmen must have taken the map and fled when One Eyed Willie was murdering his crew. This is substantiated in the novelization.