While we still do not have a definite answer as to how long he has been upset with the company, we do know now that CM Punk was already contemplating a departure from WWE as early as Royal Rumble 2014. He vented to Mick Foley at the time about not being happy within the company and having trouble dealing with injuries.
While management has given up on the character, WWE will be keeping Sin Cara around because he is featured in the upcoming Scooby Doo movie. Oficials have no plan on bringing the original performer back, so Hunico will have the role until after the movie has been released.
While the masked superstar is still interested in a return, WWE has expressed very little interest in bringing Sin Cara back now that his contract has expired. The belief is that the company can save a good amount of money by using Hunico instead.
Despite being replaced by Hunico under the mask on WWE shows, the original Sin Cara has still been posting pictures of himself with the mask on Twitter. The company is planning on keeping the character even after his contract expires in a few days.