Defective Tire Indication??

I have wondered about that myself. One dealer told me it was created when the end of two or more belts were located at the same point on the tire. I would think that would create a weak point but have been told that it does not. I'd like to see one dissected to see if that is the fact.

I've had many tires with that indentation with no failures attributable to it. Both OEM and purchased. I usually get 50K to 70K on them.