Morgana's Black Shield
I have a question concerning what Morgana's Black Shield is supposed to do. I've read that it's supposed to shield magic damage and protect from cc. In my last game, I was playing as lux and I snared the enemy players multiple times, and unleashed my combo which would've killed them. However, for some reason when Morgana used Black Shield on them it released them from the snare allowing them to avoid the full combo. I checked to make sure that they didn't have Mikael's Crucible or QQS. Is this what her spell is supposed to do or is it a glitch?