Character mistake: When Maui and Moana set sail after defeating the Kakamora, Maui says they must head east. He turns the boat 90° as he says this. Throughout the next scene the setting sun is to the left of them (providing a beautiful backdrop to their fight), meaning that the boat must be heading north, not east.
Character mistake: During the race sign up scene, when each racer is throwing their coin into the gold cup as the entry fee, the announcer says Snowanna Rainbeau, and you can see a blue haired pig-tailed character just behind Rancis Fluggerbutter. This character is Citrusella Flugpucker, the 6th listed racer on the board, but she is announced as Jubileena Bing-Bing, who is listed 13th on the board. Jubileena Bing-Bing is the red pig-tailed racer, not the blue. (00:35:10)
Character mistake: Baymax, a healthcare robot, says that his programming includes a database of 10,000 symptoms of disease. Yet, he issues the warning, "After eating, wait one hour before swimming." That warning, often given by parents to their children, has no basis in medical fact. People who do not get cramps after eating will not develop cramps by going swimming after eating: http://www.snopes.com/oldwives/hourwait.asp.