[2021] Taming help

So I've been trying to take a Hellbull. I used a whistle to ensure I knew which were tamable and then attacked the bills like every guide said to do. I have now looked 104 Hellbulls and not a single one has gotten the hearts/allowed me to tame. What am I missing here?

Os. I have the estate and when I was doing the initial taming quest the second bull I attacked hot the hearts but I had to kill the other mobs and by that time the bull was normal again. However, the quest still checked it off for me