A book, possibly a diary.
Artists for hire should be kept on a leash, particularly illustrators. Artistic license isn't an excuse for changing a story element.
Editors should also earn their money. In their quest to get out covers they have gotten careless. There has never been a overt plot reveal on the cover. Thank you editors, I remind you though, to take your stupid pills after working hours. When producing two covers at once, remember that while a plot device is revealed in one book, it should not be revealed on the second cover before the first book hits the shops.