What causes paint peel?

The front driver’s side of my 2009 Mitsubishi Lancer has what appears to be a lot of weathering resulting in a lot of brushed scratch marks around the headlight and bumper. The topcoat of the paintwork in this area has now blistered and is peeling away. The other side of the vehicle is like new.

I have had the car since new and took it to the dealer to look at. What causes this? The dealer said it might be due to a third party. What do you think?