I never said it was fact, I was speculating based on the lack of information about the death or survival of those Stormtroopers. The movies merely say they are out of combat, but they may be alive after the heroes leave the area.

And my speculation is very simple:
-Stun mode: everyone is stunned regardless of armor (or maybe some armor might absorb the energy)
-Lethal mode: an armor can save your life but you’ll get stunned if you’re hit in vital parts, if you lack an armor you’re dead