Someone on my dash wanted to know why Northstar and Aurora occasionally show up with white/silver hair in the comics or other media, and I figured I'd cross-post.
The twins sometimes still get drawn with white hair because, in their early appearances, they’re always shown with light highlights in their hair, which generally indicates white hair, rather than the blue that denoted dark-haired characters. Compare the twins to Shaman, Colossus, Wolverine, and Nightcrawler here:
John Byrne's stated he intended the twins to have very glossy, dark hair and the white highlights were supposed to indicate shine (by comparison, note how Storm’s hair is flat white, not dark with white hightlights). But it’s easy to see where someone who didn’t have that info would look at that and think the twins were supposed to have white hair.