en.pathofexilewiki.com/wiki/Elemental_Equilibrium
"In case of an enemy being hit with an attack that carries two types of Elemental Damage it will get -50% Resistance to third element. An attack carrying all three Elemental Damage types does not trigger Elemental Equlibrium."
"In case of an enemy being hit with an attack that carries two types of Elemental Damage it will get -50% Resistance to third element. An attack carrying all three Elemental Damage types does not trigger Elemental Equlibrium."