I've had a question that I can't seem to find an answer to and it's hard to formulate a question that I feel is clear enough without explaining the setup.
Lets use a 6/2 Sorc/Warlock as an example. Say the Warlock took the Undying Light patron from the Unearthed Arcana - Underdark supplement. Their 1st level feature Radiant Soul allows them to add their Charisma modifier to any radiant or fire damage they do. Next, they take the Red Dragon Draconic Bloodline for their sorcerer levels. At 6th level, they get to add their Charisma modifier to any fire damage they do. Lets say their Charisma is 16 (+3).
Does this mean any fire spell they cast will have double their Charisma damage (+6)? I can't find answers to say one way or another since it's an added feature from two different classes.
Example: this character would cast a Firebolt that deals 2d10+6 fire damage on a hit.
I assume yes, considering if it was a Tempest Cleric and Blue Dragon Sorc, you would add Wisdom and Charisma to your lightning spells and I see nothing wrong with that.