IMHO until Sammy completes their root cause investigation ANYTHING involving thermal cycling, heat dissipation, thermal cooling and charge/discharge cycling is fair game. They just don't know at this point. Logically it makes sense that anything that entraps and encloses heat can't help the situation.
Its a real problem to root cause because its a test to incendiary failure. So when a Lithium battery fails... it burns any source of data and evidence in the process. I think what they will have to do is charge cycle and thermal cycle a lot of phones and induce fire/flame and then immediately extinguish it so there's actual failed material to root cause.
I wonder if they are trying to cram too much amp-hour energy density into too small and flat of a battery shape? I guess when were talking about electrons, cathode and anode sheets a fraction of a mm is all it takes.