Kind of a strange exception here. Ice Blast is able to debuff invulnerable units

1. Buy Eul's Scepter
2. See Ice Blast coming in
3. Cyclone yourself in attempt to dodge the Ice Blast

Result: The impact damage is dodged, obviously, due to the invulnerability. But it still places its debuff on you.

Expected: Ice Blast shouldn't place its debuff on invulnerable units.