I call it a herd glitch its when the entire herd freezes and they only begin to move when shot ive had it happen on whitetail blacktail and black bear but only on layton lake
it is a bug my dad came across the same bug on a huge herd of Gemsboks' it was a total massacre he found lots of feed zones so there was loads he could barely play.
its a pretty common bug, happens to herds, offten occured on deer and wolves/
Never found a wolf yet, had no idea it was a glitch as I started playing a few days ago lol