That's NOT factory. Only Touring and Grand Touring trims come with factory (privacy) tinted glass. Sport does not. There are no OEM window tint films, as the production of the glass itself has been tinted without a film.
Your tint film is an aftermarket installation and is not covered under the manufacturer's warranty. Simply said, Mazda will not fix it. It is most likely a dealer installed film. You may want to ask your dealer about that if they didn't inform you during the time of purchase. If anyone is going to fix it or pay for the fix, your dealer is the one to do that. Be aware of how they "fix" the tint. The tint will have to be completely removed. With care, the rear defroster element will not be damaged upon removal.
Also, any quality film tint should not bubble, fade in color (turn purple/blue), and lose UV protection properties within 3-5 years. It was a cheap film and/or poorly installed. If you do happen to get it fix, I suggest going to a well reviewed tint installer using quality tint. 3M, Llumar, and Johnson are high quality tints with various levels you can choose from. Suntek also has good entry level tint. It comes down to personal preference at that point (various amount of heat/UV reflection). Any reputable tint shop should have LIFETIME warranty for their work using said brands. Quotes should be between $25-50 for every large window depending on the shop and brand/model of tint.
