Abilities such as Magicka Detonation and Scorch do not trigger the Empowered effect, even though they are mechanically classified as direct damage abilities (they are affected by Master-At-Arms in the CP tree). I have tested this with Empowered active on cast, and again right before activation, and neither works.
This does not feel like it's working as intended, since even DoTs will trigger Empowered from any of their ticks when Empowered becomes applied, so it's definitely not exclusive to immediate-effect direct damage abilities. Please look into this, and thanks!