I’m an insurance adjuster in Ohio and have seen many, many roofs with this roofing product. Most homes with this produce are typically very nice higher end homes.
I see time and time again this product with significant blistering and pitting with roofs that are anywhere from 8 to 14 years old. Some of these homes do have ventilation issues, but, this type of situation seems all too common here in Ohio.
Have you had similar experiences with this product? Is there some sort of defect? These shangles were 40 year rated at the time of installation (they are 50 year now); but, I don’t see them lasting any longer or even as long as a 3-tab.