Summoners War: Chronicles

As you can clearly see in this video it never activated off light Raven even once that entire match, regardless of hitting summoner and hitting fire Monkey King. I can only assume since it has 2 attributes you somehow made it not work since it's both "Weak point attack available" and "Ignore target's DMG Mitigation effect". And you can also clearly see fire Monkey King artifact's knockdown just ignores all forms of immunity still.

But against fire Raven a few minutes later it clearly works even against the basic attack.