Can Kai'Sa Legend pay the deflect cost for reflexive triggers like Falling Star and Icathian Rain?

Ruling: Kai'Sa Legend cannot pay the deflect cost for reflexive triggers like Falling Star or Icathian Rain. She can still pay the mana cost to cast the spell itself, and she can pay deflect costs for spells that directly target (like Void Seeker), but not for deflect costs on the reflexive triggers those spells create.

Nuances:

• The spell's damage is still considered to come from the spell for other effects (like Immortal Phoenix)
• Kai'Sa Legend can pay deflect for regular spell targeting, just not for reflexive trigger targeting
• This represents a change from previous rulings where Falling Star and Icathian Rain were treated differently