So there was a long trace of this issue happening ever since I first started playing (10/15/20).
Screen Name: sotonto
Server: Silver
I had played through my first night of the game and then I logged out and logged into from my laptop so that I could play from my bed.
After logging out, my Charmeleon, lvl24 at the time, got reverted back to level 5. We can call this level 5 charmander the "bugged charmander"
I made a request in the Discord to have him given back to me. I kept playing, leveled up the bugged charmander and logged out. Next day my old charmeleon was given back to me (I assume). I can say it was given back to me because I now had 2 charmeleons and the one that was given back to me overrode the pikachu that I had in the lead spot of my party. I put the extra charmeleon in my party and just kept playing because the "lost" pikachu was the least of my worries at this point.
Here is where I believe this issue took a turn for the worse.
Today (10/18/20) I was playing and I evolved my eevee to a jolteon. From there, there was a server down at about (Silver Server) 7pm ET. Jolteon was in the lead spot of my party. When I was able to log back in, there was a pikachu in place of my jolteon. I created another request to get my jolteon back in the Discord. I then just kept playing for about 20min, logged out and logged back in, and then the jolteon was back like no problem. There was no check mark emote on my discord request so I just deleted the request to not cause any confusion. (not sure if there was anything done about the request)
At about 11:30pm 10/18/20 I had gotten timed out from being afk. Jolteon was the lead of my party still. When I logged back in, pikachu was there instead of jolteon again. At this point I was very frustrated so I wanted to do something about it myself.
I started a random wild battle, swapped in my gyarados for the pikachu, and then logged out in the middle of the battle. When i logged back in, I saw that my jolteon was back, but my gyarados was now gone and had been made into that same pikachu.
I placed pikachu in my PC and logged out. Logged back in, My jolteon has now disappeared and my gyarados is back in my party.
That is the best information that I can provide based off of my memory of the events that happened.
The ID of the pikachu that keeps appearing over my pokemon is 51860497 and he is right now (10/19/2020 1:04 AM ET) sitting my PC Box 2 4th slot.
I really would like to get this resolved as I am having so much fun with this game and it is a shame that this is happening.
Looking forward to your help!