I created a Duergar and noticed that my spell list updated with Enlarge/Reduce, but not Invisibility. Both spells are added by the Duergar Magic trait, and upon inspecting the trait in my sheet on Beyond, I noticed Enlarge/Reduce is listed twice. I assume this is simply an error of putting in Enlarge/Reduce twice instead of Invisibility.

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

I just went to test this and neither enlarge/reduce nor invisibility is showing up for my character: (https://www.dndbeyond.com/characters/86402521).

I just went back to check it in case it was a caching issue and now both spells are appearing on my sheet twice: