when aatrox enters passive....
he does NOT completely die ,so why doesnt he keep W stacks on ?maybe you get revenge when reviving with bloodprice dmg or maybe you heal enough to survive?maybe ? why the stacks are gone? its like if he dies he would lose stacks of occult even if he didnt die(passive proc alike guardian angel) tl dr ,passive doesnt start from first stack to 3 instead remains where it was before entering statis ! QoL buff