Lux + 2 Seraph's Embrace was not full mana after a kill... very dissapoint

Lux + 2 Seraph's Embrace was not full mana after a kill... very dissapoint

Lux special is receiving 50 mana on a kill.

Seraph's Embrace is 20 mana after casting a spell. With 2 Seraph's she should have been repeat firing everytime she killed someone but this did not occur