I am new to this Mazda 6 Forums. I found this discussion thread via Google search initially.
Anyway, I have exactly the same issue as you have described. My Mazda 6 Sport Nav 175PS Diesel in Soul Red with 19"Dark Metal Alloys (delivered June 2015) <10,000 miles. I absolutely love the car but noticed last weekend that large chunks of wheel lacquer was missing from all four wheels and other areas clearly blistering/peeling. I have never kerbed the wheels and the only person to wash the car is myself, by hand and only using the provided PH Balanced Shampoo.
I have attached some photos.
I have contacted the Dealer, who first warned me about Alloy Cleaning Chemicals and Car Washes would invalidate the Warranty. Undetered it goes into the Workshop for inspection on 12th May 2017. I will keep you posted. I am expecting some push back but I am a dog with a bone on these sorts of things.
Edit : PDF attachments removed. Please read this
http://www.mazda6forums.co.uk/index.php?topic=1846.0