Scorching Rounds reduce ignition damage

Scorching Rounds, which is given by Warlock's Song of Flame and Titan's new Shieldburst aspect, gives weapons the ability to apply scorch but dose not count as a weapon damage source and as such will disable ignition bonuses from 'The Perfect Fifth' perk, radiant, and anything else that would normally boost weapon based ignitions

without scorching rounds

with scorching rounds