It's a bit weird, but an old bug -- if there is a global Spell Aegis effect out, and a spell is cast, then another Spell Aegis effect will go out. This is how it should be if there is a champion with Spell Aegis in play, but the effect persists after the Spell Aegis champion has died, so long as at least one of the global stacks of Spell Aegis is still active.
