Gaming Why Does it Mean This?

[Gohobojoe]

I want legal pokemon and after a little bit of screwing around with the PID Generator, I got what I wanted (Modest Hidden Power Grass Typhlosion)... but then I decided to put the TRU Arceus through the Platinum Legality Checker.
The TRU Arceus... Why is it that when I ran it through the Legality Checker, it came up as Mystery Gift (Hacked)?

 

[Nurio]

I'm thinking because the TRU Arceus has qualities a normal Pokémon doesn't have. Like maybe moves a normal Arcues doesn't have.

 

[Inunah]

I'm thinking because the TRU Arceus has qualities a normal Pokémon doesn't have. Like maybe moves a normal Arcues doesn't have.

Unless it's just a glitch for a special event Arceus.

 

[Gohobojoe]

Aaaah. Now it makes sense.
I suppose that was kinda stupid of me...
Alright thanks though.