I used 1 YOSHIRA Mew shared on this site for my Pokémon Blue run. I also traded Charmander and Zapdos from the Twitch Plays Pokémon savestates.
Someday I will upload it to my Blue Cartridge. It was a fun experience.
Also in Gen 2 I've been doing some shiny hunting, I use PkHex to preserve my shiny Pokémons for future Gen 2 runs.
Yes, as @theSLAYER said, we have just to wait the next release. I noticed I've the same problem with two other mons in my Pokémon Yellow VC. But I'm sure everything will fixed soon.
056 - MANKEY - FC0C.pk1051 - DUGTRIO - 3185.pk1
@PkHexBoi besides Mew (obviously illegal, you probably used the Trainer Fly Glitch or something),
Wait for the next version of PKHeX.
This screenshot is taken from a developer version.
(Ahead of existing stable release you're using)
Pokewalker encounters are Shiny Locked, so no way you can get a legal Shiny Surf Pikachu until gen 7.
Here there is a legal 6IV (31) Timid Pikachu with Surf:
025 - PIKACHU - 5B87E9000007.pk4
It's genned, not obtained in game.
Mine does not work, but i know there are some models that works for GBA too. You need to read the description of the dumper you're going to buy. Anyway, for GBA save file you don't need a dumper if you have a DS Fat/Lite with a Flash Card like an R4: