The military refer to this sort of thing as "training risk". It's bound to occur once in a while. Happened to me once, 25 years ago, during an EOL. The student inexplicably and rapidly pulled full aft cyclic at about ten feet agl, instead of raising the collective to cushion the landing. I took control and thought I had saved the aircraft from damage but the frangible skid was slightly cracked.
I was made to fly multiple engine offs with a senior CFS instructor to ensure I met instructional standards. I obviously did because they made me carry on.
