Nocturne W not blocking Swain's ult ravens

The Ravens just do what they normally do and ignore the spell shield. How to recreate:

1. Get Nocturne and Swain on different teams
2. Get Swain to Level 6 (Nocturnes level doesnt matter as long as he has a point in W it works)
3. Have Swain use his ult near Nocturne and have Nocturne use his W. The Ravens will ignore the spell shield and will not consume it, Nocturne will not gain the bonus attack speed.