Re: arrow penetration question
Not sure I can offer any input. My experience has been that any traditional bow, compound bow or crossbow of a modest weight shooting a hunting weight arrow will pass through a deer unless it encounters bone.
A 175# crossbow shooting 340fps is more than adequate for all animals except dangerous game.
With all of that said, I high hit than hits bone and does not pass through it will take a while to bleed as the cavity must fill up with blood first. Not sure that was the case with yours but just throwing it out there.
If your broadheads are sharp, I can't explain your observations.
I support all hunters, regardless of weapon or technique!