I have a Beasts/Nature MM and whenever I'm fighting COT I've noticed that Behemoths enjoy the same buffs as my pets when I lay Life-giving Spores down, I sit and watch as everything else falls before my bestial horde but the Behemoths are still battling away on full health. The moment I drop Life-giving spores they get torn to shreds.
Weird for a player buff to have a direct effect on foes.