Leaks usually come in the form of product catalogs, which are given to retailers, which would meant that they have plans to put them on their shelves. It really depends at what specific time the theme got cancelled. We know that it was decided during the Netflix show's script for the summer was written. Would they already have made all the sets for 2017 and gave out retailer catalogs before then? Because if not, then the prototypes would be strictly within the firm grasp of Lego.