[Gameplay] Nasus' ability to ignore most anything

I noticed in a Sivir Game today that Nasus' Siphoning Strike (Q) was going through Sivir's Spell shield, wanting to test this out further a snagged a buddy and went into a Custom game to see if this bug was also effecting Nocturne; the test results for Nocturnes W and Banshee's veil showed that both did not stop any of the damage from Siphoning strike. Short terrible quality video of the tests here : https://www.youtube.com/watch?v=19UIlUyb3-8&edit=vd (let me know if this isn't working properly)

Doing a brief search of the Bug Report forum shows that this bug isn't limited to just Spell shield or just Siphoning strike, as people have also reported it going through Jax Counter Strike, and happening on Spirit Fires initial cast. There was someone that believed it could be a bug with sheen, but from my tests that is not the case.

Another possible bug with Siphoning Strike, is that it may be ignoring Turret defenses, unless a 300 stack Nasus without sheen or AD should be doing ~500 damage to the new turrets.