Aatrox w counter resets upon entering passive

Example: Prepare w for the proc then get "killed", when you respawn from passive the w proc is gone.

Why is this? When you have Guardian Angel I'm fairly certain this doesn't happen, as well as when revived from zilean ult. (I haven't had those happen for a while so maybe I'm remembering differently)

The only thing I know that resets it like this is dying, hence why I'm confused.

If I'm just wrong, could this be altered? It feels really bad when playing.