When Tummi and Grammi are going on their search for Sunni, they go up the stairs and see Sunni and Princess Calla coming down. Grammi cries, "A human!" and hides her face in her apron. However, two shots later, when Sunni tells her it's all right, Grammi hides her face behind her apron again.
Just before the real Princess Calla transforms into Duke Igthorn while wearing the changing hat, there is a glimpse of her wearing her regular, blue, princess dress rather than the blue, raggedy, peasant dress.
After an ogre asks Duke Igthorn, "What little guest?", there are whites in the ogre's eyes instead of yellow. In the next scene, the ogre's eyes have yellow in them again.
When Calla is in Igthorn's form and asks Toadwart if he can tell she's him, she calls him by name so the hat should turn into him, but it doesn't.