Tarzan (1999)

Deliberate mistake: When Tarzan fights with the leopard, it scratches his chest. However after they fall into the pit and Tarzan comes out carrying the dead leopard, the scratches on his chest have amazingly healed. [It is a long-standing Disney tradition that no evidence of violence is shown on screen. Still a mistake, but there's why].

Young Tarzan: I'll be the best ape ever.

Trivia: At the beginning of the film, when baby Tarzan is blowing spit bubbles, the bubbles look a lot like Mickey Mouse. It's a long standing Disney tradition to put "hidden Mickeys" in their movies.