Mystery Mew illegal?

[Araraura]

Is there any reason why Mystery Mew turns illegal once I change the met game? On PKHeX, it's considered legal if the met game is Ruby, but if I change it to other gen 3 games, it suddenly turns illegal for some reason. I checked on both serebii and bulbapedia, and they both state that Mystery Mew was distributed to all Core Gen 3 games.

[theSLAYER]

14 minutes ago, Araraura said:

Is there any reason why Mystery Mew turns illegal once I change the met game? On PKHeX, it's considered legal if the met game is Ruby, but if I change it to other gen 3 games, it suddenly turns illegal for some reason. I checked on both serebii and bulbapedia, and they both state that Mystery Mew was distributed to all Core Gen 3 games.

It was distributed with the data for "Met Game" already set.
so yeah, if you change that, it'll be illegal.

[Sabresite]

Almost all distributions except PCNY have a met game of Ruby. It's static.

Here are all 430 Mystry Mew:

https://github.com/projectpokemon/EventsGallery/tree/master/Released/Gen 3/ENG/Toys R Us/MYSTRY Mew

Your Mew must match exactly!