Continuity mistake: After Dory reads the wall map while she's in the glass carafe, when Hank hides behind the rolling cabinet there's a long shot of the corridor with him at the far wall, then in the next shot from behind Hank a drinking fountain has suddenly appeared on the wall to the left, between two pictures.
Continuity mistake: When Dory reads the word "Destiny" on the white bucket, its handle is attached over the letter "t", but when Dory forces the glass carafe to tip over, now the handle is attached over the letter "e."
Continuity mistake: When Carol, the MLI employee, is first seen carrying the white bucket in the corridor and also when Carol thinks she located Hank, the bucket has absolutely no writing on it where the handle's attached on both sides, but when Dory looks down at the bucket suddenly "Destiny" is written on it.
Continuity mistake: When Dory and Hank are in the stroller trying to get to the Open Ocean exhibit, Hank steers the stroller right into a girl wearing a striped top and holding a cup of popcorn, but a few shots later that same girl is now wearing a light pink top when she's on her knees with the spilled popcorn.
Factual error: At the start we see some neon tetra in the background. Tetra are fresh water fish. Not saltwater. (00:05:00)
Continuity mistake: While Hank camouflages himself as part of the yellow banister, Carol, the MLI employee, walks down the stairs with the bucket, and when she sets it down the handle falls to the side of the bucket facing away from Dory toward the staircase, but in the next shot the handle is facing the opposite way. Additionally, the bucket's distance from the floor's black-yellow caution stripes decreases between these two shots.
Continuity mistake: When Nemo approaches the sea lions he is in front from the rear angle. From the front he is behind his dad. (00:24:10)
Continuity mistake: At the end, the truck jumps off the cliff into the sea. We see the truck flip over 90° so the trailer doors are starting to face forwards and the cab faces back, upside down. Camera changes and the truck has gone back to being right way up, and not rotated nearly as much.
Continuity mistake: Hank pulls Dory's tank on the trolley closer to him, then a few minutes later does the same thing.
Continuity mistake: When Dory is captured by the MLI boat, we see a wide shot of the sea and there is no boat, then it suddenly appears to catch Dory. (00:12:00)
Continuity mistake: When Dory is at the school at the start, there is a bug eyed fish that is by Nemo in the back shot and by another fish in the front shot. (00:09:10)
Chosen answer: In the absence of a neuropsychological work-up, we have only Dory's word for it: "I have short term memory loss...It runs in my family...at least, I think it does." So, Dory believes it to be genetic. At least, I think she does.
Michael Albert