That blister is about to pop! Ford has been fighting corrosion on their aluminum hoods since they started in the 90's with hoods for weight savings. My 2012 mustang has chipped all along the nose. There was a class action about this at some point. "Corrosion" is technically defined by Ford as rusted through metal, meaning you can see through the sheet metal. Clearly aluminum won't have that capability but it still looks like s*$!. Stay frosty while you're under warranty to have this covered. Look at hemming around the door also if you're in a cold climate/salt. Some guys are coating their brand new trucks, ceracoat?? I don't know.
My understanding it is iron oxides deposited on the aluminum during forming operation- stamping dies, hemming tools; then coated with primer. That wear from the tool steels onto the aluminum isn't an easy fix. I can't imagine how to wash a tool in a 20 spm transfer line, the only option is washing the part after forming which i'm sure this is done to clean lubricants and primer prep; but it's not cleaning well enough if so.