Does damage dealt by Searing Blood's delayed trigger cause Satyr Firedancer to trigger?
The ruling is incorrect. The source of the damage is the Searing Blood spell. When Searing Blood resolves, it creates a delayed triggered ability


  When that creature dies this turn, Searing Blood deals 3 damage to the creature's controller.


The "Searing Blood" in the triggered ability refers to the spell Searing Blood, so when the triggered ability resolves, the spell is the source of the damage. Since the spell no longer exists, its last known information is used.