Yeah, they don’t know what they are talking about.
They made up the “decapitated” part, and then invented a tumbling bullet to help the decapitation story.
He was shot in the head with .338 Lapua round.
It’s possible the shot hit a little low striking the neck, not sure if the round would still have enough energy to completely sever the head at 1000 yards but is would certainly loosen thing a bit.
I’ve seen a guy who appeared to have a severed head but when we moved the body, it was still attached, it was just hanging behind him.