'Unable to match an encounter from origin game' even though a trade evolution went through

[Morghini89]

So I just did a trade evolution with my friend regarding Gourgeist sizes in Pokemon X. So I went on to PkHex and I see the legality checker was saying the small and super size were illegal. Although I caught these Pokemon in the wild and trade evolved them, they're still being marked as invalid. What do I have to do to fix this problem? It's only for that Pokemon!

Edited May 10 by Morghini89
Correction on information provided

[Kaphotics]

9 minutes ago, Morghini89 said:

So I just did a trade evolution with my friend regarding Gourgeist sizes in Pokemon X. So I went on to PkHex and I see the legality checker was saying the small and super size were illegal. Although I caught these Pokemon in the wild and trade evolved them, they're still being marked as invalid. What do I have to do to fix this problem? It's only for that Pokemon!

Without seeing the pk6, can't tell. Likely a problem with the hidden ability/ball, since that's not possible for those forms depending on the encounter.