Hecarim E not being absorbed by Spell Shield

I was playing Sivir and whenever Hecarim was using his E I would use my E to spell shield it and I wouldn't get pushed but I still took all of the damage regardless. Is this a bug or is this working as intended? It does not make sense for it to stop the push back but not the damage or vice versa. This happened every time I used my spell shield against Hecarims E.