Gen 4 Diamond - Shiny Shaymin caught legitimately - PKHex says its not legit. Why?

[VirtualTurtle]

Hello! I modified my diamond save to enable the shaymin event + oak's letter and did everything except actually receive the mystery gift from the pokemart. I spent two weeks doing run-aways until I found my shiny shaymin! The only issue is PKHex says it's invalid.

- Unable to match an encounter from origin game.

- Static Encounter Shiny Mismatch

This doesn't add up to me. the only illegitimate thing I did was enable the event because it ended 10+ years ago. I had already gotten the national dex and I was using real 3DS hardware & real cartridge to do this from an entirely homegrown save file, why would Shaymin be considered not encounter-able or shiny-able in my game? is it detecting a mismatch between the pokemon & a setting I missed in the save file?

I've attached both the sav and the shaymin .pk4. Please let me know what is wrong since I spent two weeks trying to get this guy naturally/as legit as possible.

492 ★ - SHAYMIN - B94B8A561EA6.pk4 POKEMON D.12.sav

[ERNESTO JG]

Solo en Pokémon Platinum

[VirtualTurtle]

Just now, ERNESTO JG said:

Solo en Pokémon Platinum

Ah! I guess I didn't do my research then, he's not available in diamond. I could hunt him in platinum again, but honestly I might just change the origin game and call it. Thanks

[ERNESTO JG]

5 minutes ago, VirtualTurtle said:

Ah! I guess I didn't do my research then, he's not available in diamond. I could hunt him in platinum again, but honestly I might just change the origin game and call it. Thanks

Aqui Tienes uno de Pokémon Platinum

 

0492 ★ - SHAYMIN - 411AFC0A7D30.pk4

[theSLAYER]

There’s no way to catch Shaymin in Diamond/Pearl legitimately; the event wasn’t distributed.