Bug or poor wording on Nihilist Paralyzer

Nihilist Paralyzer’s current trait right now is
After a creature is killed, your creatures gain 50% of its Attack. This trait does not stack.

Problem that someone is having with this trait is that it’s not activating under the conditions mentioned in the trait, I’ve tested the trait and so has someone else, and the trait seems to only activate when Nihilist Paralyzer itself dies. Its trait does not activate when another creature is killed.