This leak is not normal from the game files, it comes directly from the source itself.
On the official Instagram story for Fortnite Game, the company accidentally posted a picture of the skin I had never seen.
A blue elf with frozen wings on her back, the skin looks pretty clean. Here's a screenshot of the quickly deleted story:
This skin will almost certainly be the next post of the day, but there is definitely a social media manager at Epic in hot water now.