When Maleficent is flying after growing up, her necklace disappears and reappears.
The playing pieces appear and disappear on the board game that Flittle and Knotgrass are playing.
When Aurora meets a dragon-like creature in The Moors, Maleficent calls her over to sit next to her. The dragon follows Aurora to the tree and then passes behind it. When the camera angle changes, the dragon should be behind Maleficent's head, but it has vanished.
Shots of Aurora as a baby arriving at the cottage for the first time show she is wrapped in the king's cloak. The basket is carried inside, but in a subsequent shot, we see that the same shot of the baby in the basket is used (with the cloak). When the camera angle changes the cloak is gone.
Flittle pelts blue on Knotgrass's face while they're playing a board game, and the camera turns away briefly. When it turns back to the fairies, the blue is gone.
Spinning wheels don't have sharp spindles, and most drop-spindles are not sharp enough to puncture skin. The distaff on a spinning wheel, however, is often this sharp. The distaff is the pointed bit that holds the wool (or other fiber) waiting to be spun. Disney has perpetuated this falsity to the point where few American children know the difference.
Fairies are shown to be burned by iron in its metal form. This is a different form of iron to that found in mushrooms, so it is not a contradiction to show mushroom fairies or mushrooms growing on the moors.
Maleficent's curse is for Aurora to fall into a "sleep like death, from which she shall never awaken". While some have interpreted this to be backwards, a "sleep like death" is just "death-like sleep" in a different order.
Whenever the human Diaval's beak-like nose is backlit, we can see the shadow of Sam Riley's actual nose underneath.
The two kings in this story set in the Middle Ages, which ended in 1453, are often addressed as Majesty. The first monarch addressed as Majesty was Charles I, King of Spain, who was also Emperor of the Holy Roman Empire as Charles V, and who reigned in the 16th century.