It’s because when Shiny Pokemon were first introduced the Shiny Marker on their profile just shifted their colors over to the next palette, only rarely do people actualyl sit down and say “Yes, I want this Pokemon to have a shiny that’s THIS color!”, some Pokemon have had their Shiny Colors updated over the yeras (the most famous example being Charizard going from Barney to Edgelord)

Most haven’t sadly

For whatever reason when you move palettes around on the Game Boy Color they became Green… For some, with the right shade the Green is fine because it’s meant to mimic the colors of the original Game Boy.

The ones that I absolutely think need to be updated, like, it shouldn’t even be a question… are the “Identicals” the ones like Garchomp and Gengar where if you squint and look at pictures side by side… You may be able to figure out which one’s the Shiny and it may only take you the better part of an hour!

It would have been nice if they changed Gengar’s Shiny Color to White to match the Mega’s Shiny color

I mean if it’s an engine thing, I’d like to introduce different shinies… maybe a rare “Super Shiny” that’s a better color than Puke Green?