Spell Sheilds Bugged

Nocturne and more notably Sivir's spell shields have been bugged lately. For example in a game I played recently our Leona ulted onto a Sivir who used her spell shield to block it, when the spell hit she received mana, said one of her taunt lines, and still got stunned by the ultimate. Another example was a game I played as Sivir and I activated my spell shield against a Yasuo whirlwind; I received mana from the shield, said a taunt, but was still knocked up and then ulted onto by Yasuo (I'm not saying it should have blocked his ult obviously). I can't give any Nocturne examples since I don't play him but I have heard reports from Nocturne players having similar issues.