Continuity mistake: In the opening scene where Data is using his sticky dart on his belt and being dragged towards the full bin, it changes to being empty just before being pulled in! (00:03:50)
Continuity mistake: At the very end on the beach, Chunk is wearing a knit hat, but Mouth is not (he took his off earlier). Then in the shot looking up at the Goonies, who are circled around the hand holding the jewels, Mouth is now wearing a knit hat and Chunk's hat has vanished, but next shot they've switched back again. (01:46:30)
Visible crew/equipment: When Francis Fratelli walks across the beam he slips and does a flip. In the wideshot, we see the sudden appearance of a riveted platform affixed to the beam, extending from its left side, directly in front of Francis. (01:18:00)
Visible crew/equipment: When the Goonies are first climbing the ladder on the pirate ship to find one eyed Willy's gold, the second shot has a crew member waving his arm on the far left of the screen. (This is only visible in the widescreen version). (01:21:00)
Continuity mistake: When Brand tells the others that the $50 bills are fake, Stef takes the newspaper with the Fratelli family mugshots off the post, from over the telephone. Then when Chunk gets the ice cream out of the freezer, the newspaper is back up on the post, but when the kids lift the dead body off the floor, the newspaper is missing from the post. Finally, in the shot just before Chunk shouts, "Guys, I'm stuck with the stiff," as the kids run into the fireplace, the tired newspaper is now lying on the printing press. (00:42:45 - 00:45:15)
Continuity mistake: When Mrs. Walsh shows Rosalita the house, the attic door is open and we see that it opens at the left, with the wallpapered wall behind it and nothing in front of it except the banister. When Brand opens that door and the boys rush up, we see the wallpapered wall behind it, only this time the attic door opens at the right. (00:11:25 - 00:13:50)
Revealing mistake: When Brand finds the skeleton key in the dirt, he holds it up as Mouth wipes the dirt off the three holes. It's actually quite funny seeing what is supposed to be Mouth's hands in the close-up, with its female manicured fingernails. (00:55:40)
Revealing mistake: In the scene in the cave where Brand pulls back the rock and the bats fly out, there is a close-up of Mouth with bats flying in front of his face. You can clearly see the wires attached to the bats.
Continuity mistake: When Chunk waits for the gate to open after doing the 'truffle shuffle', a red balloon starts to blow up, but next shot it's a pink balloon that pops. (00:07:40)
Continuity mistake: When Mr. Perkins delivers the papers to Brand at the house, the men are holding umbrellas. The umbrella handle on the left is facing outward, but after it cuts to Brand then back to the men, it is facing inward and then changes again after another angle change.
Continuity mistake: In the scene where Mikey, Data, Mouth and Chunk enter the restaurant, when Mama Fratelli asks, "What do ya want?" Jake Fratelli is behind them with his hand on their shoulders. When the angle changes Jake Fratelli is at the back of the restaurant walking away. (00:30:20)
Continuity mistake: When Brand takes Data's sister's bike, there is a horn affixed to the handlebar which disappears when Troy pulls up beside Brand in his car and then reappears when Troy starts speeding holding Brand's arm.
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.