I grabbed all 3 quest from Eris, got them to the point where I needed to finish the quest in the mission on legend, hit all the sets with whisper and finished the mission. I can use the perks that are unlocked by the intrinsic like field prep, but I can't actually change the intrinsic, so even though I completed the quest I can't change any of my barrel, mag, or stocks. Not even when trying to craft a new one. Tried doing another legend run to see if that would fix it still nothing.