Gengarite Quest - Pokemons stayed in my party after I leave area, and Arcanine missing from my Pokemons for the quest

[Xdonuts]

I tried to Halloween Gengarite quest yesterday, upon entering I found out I have only 4 usable Pokemons instead of 5, Arcanine is missing, and when I leave the area, 4 of the Pokemons for the chess quest stayed with me in my party (left it in my PC now). I did not use them as not to break any bug abuse rules.

 

For the Arcanine I had obtained it when I did the dark realm, Darkrai quest. I went to check on my storage and notice it was missing. Could have accidentally released it last, (or previous) week while I. Am clearing my storage box. Is it the reason that releasing dark realm pokemon will not appear on the Gengarite quest?

 

I have hence posted a recovery post on discord regarding this. Hopefully it could be solved.

 

Attached are the Gengarite pokemons I got when I leave the quest area.

My IGN is Xdonuts

 

Advance thanks for the assistance