Here's my take...
If she was quartering away and moved you my have smacked her dead shoulder(kind of like a person's tricep). The arrow may have never penetrated the chest cavity. In which case she will bleed, but may not die. Good luck searching for her. Are the ferns tall enough to cover her if she was dead in them? go back to last blood, check every direction, also see if she may have doubled back.

I hit a doe very similar to this one year but got just enough to poke one lung. We waited one, maybe 2 hours, then took the trail easy. Were able to track right up to her for a finishing shot.