Jolteon GX - SM173

Can someone pls explain how jolteon dropped from ru to pu in gen sm to ss Im very new to competitve but I want to know it dropped in1 gen it

Jolteon GX SM Black Star Promos Pokémon - The online marketplace where any private and shop can buy and sell Magic the Gathering , Yu-Gi-Oh! and

jolteon sm Buy and sell Jolteon GX singles in Europe's largest online marketplace for Pokémon Easy, secure, best prices

jolteon bulba For Pokemon Sun on the 3DS, a GameFAQs message board topic titled Pokemon SM Daily Evolution Poll Day 26: FlareonJolteonVaporeon Mega