Misprint, otherwise functional.
 
You can't really see it in this picture, but there's a slight coloration problem on the cat's head. I couldn't get a good photo of it because the coasters are so dang shiny. All the weird shapes and lights and darks are actually just reflections. The actual misprint is barely noticeable. 
 
4" x 4" hardboard coaster for all your drinkies