Bisch, no way of knowing what happened ( oblique shots) but another thing that we need to watch for is if using wide heads, they will, if, hit right, not go thru point first but rather skate along a surface until it cuts, no matter how sharp it is.
Wide heads and severe angles mean it might not be touching with the very point, but rather on one of the sides ( deer / pig / blind ).
I believe that is why we sometimes see huge gashes, especially using Simmons heads. That is great if it goes in finally and kills the critter, but not so great if it just lays them open to die sometime later.
ChuckC