A recent update changed the color labeling on decks to be mana on cards AND land that can produce that color instead of OR, and I really appreciate that. (although this change has yet to apply to the default colors when searching for cards for the deck)

but I have a unique problem where I have Kaheera, the Orphangaurd(G/W hybrid mana), Fiend Artisan (B/G hybrid mana), and either Rustvale Bridge or Drossforge Bridge(needed more indestructible red sources), which puts either white or black in the mana symbols of the deck when it's really neither.

My suggestion is to not count a color from mana costs if it only comes from hybrid mana. (*unless both colors are only from hybrid, in which you'd default to the current system or something)