radiant grief lace hood + original sin

Enemies not taking damage with both items equipped

Not taking damage at all or from Radiant Grief's ignites?

Original Sin converts all elemental damage to chaos, but only fire damage can ignite innately.

"Enemies in your Presence are Ignited as though dealt 100 Base Fire Damage" converts to
"Enemies in your Presence are Ignited as though dealt 100 Base Chaos Damage" which effectively means "Enemies in your Presence are Ignited as though dealt 0 Base Fire Damage", unless you have something allowing your chaos damage to ignite (the last part is a guess).