You’d polyjuice another human into Hermione. Thus, when the imposter dies, there would still be the “dying-soul-magic” of a human dying.
Does this sound like someone polyjuiced into Hermione to you?
There was a burst of something that was magic and also more, a shout louder than an earthquake and containing a thousand books, a thousand libraries, all spoken in a single cry that was Hermione; too vast to be understood, except that Harry suddenly knew that Hermione had whited out the pain, and was glad not to be dying alone.
Does this sound like someone polyjuiced into Hermione to you?