Fire exposure & Ramako Sun's Light Ascendary

Ascendary states:
Nearby Enemy Monsters' Fire Resistance against
Damage over Time is -20% while you are Stationary

Im Stationary & rightly so the Is the enemy exposed to fire? checkbox changes nothing.
Yet im losing 9% damage when deleting the Fire Exposure Implicit on my Gloves.
Also the Fire Exposure you inflict from the Fire Mastery increases my damage.

Whats the difference?
Am i actually hitting anything since its a Cast on Stun Firestorm?

And is -20% fire res and Covered in Ash (20% increased fire damage taken) the same outcome?
Means could i get rid of the implicit?