Valve have not uploaded Kjaerbye´s new signature that was submitted by the player. It seems to be a delay in communication between the player and the Game Developer.
You didn't add my new sticker @csgo_dev please contact me before you release the new stickers in game.
— KJAERBYE (@KjaerbyeCS) July 7, 2017
This was posted publicly via a tweet and Kjaerbye hopes that Valve can update their stickers with his new sticker. The new sticker is shown below for anyone who wishes to have it.