This particular performance was terrible. Arguing about what caused that is kind of silly. No one here will ever know.
Did you hear Adele at the Grammy's?
It was the most godawful atonal thing. I suspect that she always benefits from pitch correction, but this
time it must have failed, and she and was unmasked. She and the media tried to make up some excuses, but that was no microphone problem; a mic only
amplifies what is coming out of your mouth. No effect on pitch whatsoever.