They can eat and still gain the trust from your dead dinos even if they are on aggro and have glowing eyes. So even if its coming at you full speed enraged dont immediately lose faith and drop the body too early,also you need to carry the corpse first to gain its trust because even if it eats the corpse if you didnt carry near it,it wont work. Also dont be a coward with the corpse you are carrying,especially if its a baby rex. If its fighting something,yeah back off. My tip about it eating while aggro doesnt count if like 3 seconds pass by after it kills something and doesnt smell it first