How come Swain ult doesn't drain stealthed/enemies in bushes?

If you don't have vision on an enemy champion whether they are stealthed or in a bush right next to him that he doesn't have vision in his ultimate won't do any drain damage. Easy to test this, have an Akali use W and stand in her shroud with an enemy Swain having ult active and standing in the shroud. Or have a Swain ult then walk into a bush he has no vision in.
Report as:
Offensive Spam Harassment Incorrect Board