This was a fight just after you first team up with Erin in the Darchlight Caves, after gaining access to the Darchlight Mirror. You have a double battle with some Bladestar Grunts, one of which has a Grunt with an Absol.
Absol's ability Illusion Cutter is altering pokemon's form. A before and after of my Flareon, for instance. I had to change it back with a Debug menu after the fight.
Edit: It also permanently changes the form of any Allied pokemon that was on the field with Absol; Eg: See the third attached picture. Erin is supposed to have a Aevian Ampharos but it got changed to a normal one and stuck that way for the fights afterwards.
Hard to screenshot, but, the move 'Rototiller' says it buffs Attack and Special Attack, but, buffs Special Defense and Special Attack instead when used.
Edit: Also, the move Sulfuric Acid does nothing when used.
There's a few errors that pop up, in fact. There's a magma grunt in 7th street and A double battle (Unavoidable) When you infiltrate Devon Corp that will hardlock your game and you'll need to reboot. Feels like this mod may be dead in the water until the creator returns.
Also hope the Aevian Feebas bug gets tuned up!
Edit: Evolving Normal Zigzagoon with a Dread Plate for a Galarian Linoone does not work. It only evolves to Normal Linoone. I've yet to test it with Normal Linoone to Obstagoon due to using the Level Cap password.