The "end_portal" item when in inventory or as an entity on the ground appears as black and pink squares, also when you have the item in hand it is blank, but if you place the "end_portal" the placed block will have the "space" look that it normally has.
Environment
Windows 8.1, Java Version 7 Update 51
This ticket has been marked as a duplicate of MC-48102, in favor of the more general or better information provided.