I wonder what happened.

IMO their shredder does not look very safe. It's a device that can cause digital amputation and entanglement and operators are exposed to it 100% of the time they're using the machine, which would classify it as a high-risk hazard. It really should have guarding to make the hazard inaccessible, like a longer infeed chute and a start/stop interlock that prevents it from running unless there's a bin underneath. I suspect it's going to be hard to argue that procedure & policy were appropriate ways to address the risk.