I was able to get Like a Wounded Beast working eventually, although it took several tries. Seems a bit buggy, but I can confirm that it IS possible. I also think it's an extreme outlier in difficulty compared to the rest of the weapon achievements, but that's a different story. My several tries mean over 4 hours. So, yeah i'm sorry, however this is nowhere a forgettable bug, nor a "will work eventually". I also tried with different maps and enemies. Even doing a 10 enemies kill streak with no Hp regen at 10% HP while only using skill 1. Considering you got it, please specify: profession, location, enemies, used skills, how long under 10% HP and on how many enemies you killed in a row. South of the renown heart near the Forge, there's some empty hallways with spiders in them. I gathered up several spiders, let them get me low health, then popped Endure Pain on my warrior and AoE'd them down with axe 5. The only surviving one I kited and threw axes with axe 3 to get it. There's a couple others on reddit saying that spot worked for them too. Another thing that is hopefully a bug: the Heroic Dragonsblood weapons appear to lack infusion slots (at least the 3 I've crafted). If that's not a bug, I'm not even sure what to think.