Are illaoi's skillshots supposed to be invisible when used from a Brush?

I've had multiple illaoi's hit me with Q's and E's from a Brush where the skillshot remained invisible. I only saw an animation when it had already hit. I was wondering if this is supposed to happen or not? It also happend when she used her Q over a wall where i didden't have any vision. I took damage without seeing what hit me.