What did she do about the gas system? The port that leads to the gas tube that transmits combustion gasses to the bolt is usually fairly close to the muzzle. If she cut the barrel too far back, she’d have had to rebuild the entire system.
After watching the video, it’s clear she ruined a perfectly good semi-auto rifle by cutting its gas tube. Not a very bright woman.
It will still function like a bolt action, yank the charge handle per shot. The SBR rules apply to all rifles, not just semiauto.