Leona E and spell shields.

Before hand, the way Leona's E worked vs spell shields was that if, for example, Sivir shielded Leona's E, Sivir would shield the mini root and the damage attached to the E, but the dash itself would still go through considering the shield had already absorbed CC

However, I just got out of a game where in one instance Sivir shielded my E and the dash did not complete. Is this a bug? Or was this changed? Because I have no recollection of it being mention in Leona's changes.