i play a warpath/fire pala, with smite passiv cast and the item dont work on the passiv smites . so i think is a bug. i mean the selfignite for fire spelldamage.
Immolator’s Oblation
(46% to 100%) Chance to Ignite yourself when you use a Fire or Necrotic Skill
+(4 to 6) Spell Damage for Fire and Necrotic skills per stack of Ignite on You (up to 40)