Malzahar Spell Vamp with E

[Gameplay] I have noticed that I get the spell vamp for my first E with Malzahar, but once it spreads to something else I no longer get the spell vamp. Has anyone else noticed this?

To reproduce:

1. Get spell vamp (i.e. Will of the Ancients)
2. Use E on a low health minion
3. Let your E spread, notice no health is being given to you by subsequent Maleficent Visions