Anti perforation Warranty

The reason I raise anti perforation warranty is I have significant blistering on the underside of the bonnet around where the hinge brackets are bolted to the underside of the bonnet.

The car is only 4 years old and the last body inspection carried out by Mazda was last March at the 3 year Service. Fourth year service done at an independent with mazda parts & fluids, so able to get service recorded on Mazda Digital Service Record.

Comprehensively done and documented a body and paint inspection by myself.

Not as if the areas mentioned are exposed to stone chips, salt or anything else I can think of that would cause blistering from the outside in. So thinking from the inside out (perforation?).

Anyone any views on my chances of a claim?