If the arrow passed through did is not go in the ground? If so, is it possible the blood came off going into the ground?
Sorry if I'm a skeptic, but until I see an animal that is dead shot with a mechanical with field tip sized holes on both sides I'm leaning more toward hunter failure than broadhead failure.
If blades break off, or a ferrule snaps that is one thing, but it is a near impossibility for a broadheads blades to not open. Especially given the design of the broadhead you are using...
I just don't see how that broadhead could pass through even cardboard without those hooks catching.
Like I said, call me a skeptic.