Creating a Dragonborn Rogue, copper draconian ancestry. Breath weapon defaults to fire damage, rather than acid damage. Title shows up as “Breath Weapon (Brass)”. I have been unable to find a way to change the damage type. ——EDIT—— never mind - found my issue

Please post a link to your character sheet so a Mod or Staffer (not me) can look into it for you. 

Never mind... not an issue, just operator error

Could you perhaps explain what you did to fix this? I'm having the same issue. I created my character with Red Dragon ancestry. It still shows Red Dragon in the builder, but no matter what option I pick, the breath weapon always shows the one for a Copper Dragon on the character sheet.

https://www.dndbeyond.com/profile/Sir_Prize0/characters/60076166

As a Dragonborn Sorcerer you have two ancestries, one for your Race (Copper) and one for your Class (Red).  The Breath Weapon is a feature of your Race, so if you want to change this to fire damage, you need to change it in the Race tab.

what did you find the issue to be? I have a red dragonborn breathing a line instead of a cone and only one ancestry.

Quote from RunnamucMessin >>

what did you find the issue to be? I have a red dragonborn breathing a line instead of a cone and only one ancestry.

 
Please post a link to your character sheet so someone can look into it for you.