Willpower bugged?

I was doing by act 4 exploration and i noticed something. I was in 4.3.2, my warlock got inflicted with some passive debuffs but willpower didnt activated, i thought that maybe will power doesnt work against passives, but thn i got inflicted with non passive stun, will power didnt trigger een though i wasnt having any healblock. But whn i tried my domino will power was working fine. Is there something with warlock willpower interaction??