TR brings up a good question with how the factory installs seats. Press in or bang them in. I know some manufactures pull the seat into place as it is pushing in guide. Anyway, I would assume HD is not new at this.
Something I would of liked to see with the vid and pics is the clock angle of the flaw. Are they under the port at the thinnest part of the head? Is the 2nd seat adding to this problem by putting more force in this area?
Not a head guy so I might not be using proper nomenclature. BUT I am trying to describe a problem that one can get into by over boring a seat to what it was meant to, and puts pressure to the underside of runner at a higher psi because the lack of material to spread out that load.