mordekaiser Q interaction with rilay and spellvamp

why does it apply 33% ,1/3 effect rilay and spellvamp? Spell vamp is reduced to one-third effectiveness. Rylai's Crystal Scepter will apply a 40% slow for 1 second. Q is single target ,counts as aoe ?aoe was pre rework W is aoe ,low spell vamp and slow effect E aoe ,low spellvamp and slow effect R single target ,working as intended ,normal slow

weird interaction you know,gunblade or wota could have been good , thats like saying vlad Q heals for 33% not 100% with vamp

bugged?