Problem with Kupo's Spell.Cast

Pretty simple



Why does this work?

Code:

---

Actionmanager.DoAction("Ninjutsu", Core.Player.CurrentTarget)

---

but this doesn't do anything?

Code:

---

Spell.Cast("Ninjutsu", r => true, r => Core.Player.CurrentTarget)

---

Problem with Kupo's Spell.Cast