Deliberate "mistake": At the elephant graveyard, little Simba claws Shenzi in the face. When Mufasa saves Simba from the hyenas, the cuts are gone, a few seconds later. [This was done intentionally, I'm sure, for two reasons. The first being, Disney doesn't let fresh scars linger on the screen too long. Secondly, during that same scene when Mufasa rescues Simba & Nala, he claws Banzai in the rear. To stress the point later in the movie, that severe scar is shown too, but only briefly, it too disappears because of reason 1. Still a "mistake", but there's why.]

Continuity: When Timon rides Pumbaa through the vultures that are crowding around Simba, they run right over where Simba should be, but he's not there. 2 seconds later, after all the vultures are gone, Simba is back.

Factual error: When Mufasa is showing Simba the kingdom from Pride Rock they are facing the sun, yet Pride Rock's shadow is visible below them. Also in the same position, you see that they have shadows behind them. Then a few seconds later when Simba sees the shadow area the shadows are in front of them while you can see part of the sun to their left side. They would be facing south when the sun is east. How are their shadows in front of them?

Continuity: Nala's eyes change from blue to green quite often during the movie.