Misshaded

He has arrayed Duessa in the radiant habit of "Heavenly Una with her milk-white lamb;" he has claimed for incarnations of revenge and guilt, that reverent affection which is due only to innocence and mercy; and over countenances, whose misshaded leprosy would look ghastly as the face of Death itself, has spread a veil of flimsiest sophistry, yet withal so artfully and curiously interwoven with gems and pearls of truth, that the eye of the spectator too seldom pierces the seductive disguise.

Source: wiktionary

You can use the Eraser icon to erase a misshaded tank ( a factory reject, perhaps), and recopy or reflip the model.

Source: wiktionary

For rendering purposes this problem can be ignored, with the result being one misshaded pixel once in a great while.

Source: wiktionary