There were about 100 reported incidents out of something like 2.5 million Note 7 manufactured, so whatever the defect is it is not a common one and thus hard to

There were about 100 reported incidents out of something like 2.5 million Note 7 manufactured, so whatever the defect is it is not a common one and thus hard to find and confirmed. Not to mention most of the phones with problem burned so you can't "debug" them directly.