GF seems to have gone hard on retconning this gen, normally we see stuff like abilities, movepools, and in the cases of Gen 2 and 6, adding new types.
While these are pretty big changes it seems that the minor ones like changes to evolution methods and egg groups that seem to throw most people off. Eevee evolving into Leafeon and Glaceon using a Leaf Stone and an Ice Stone and Gardevoir being put in the Human-Like egg group are examples of retcons this gen.

What are some retcons you would like to see? These could be changes to abilities, items, game mechanics, evolution methods, etc. that would in some way affect the "continuity" of Pokémon game mechanics.

Mine is pic related, I think they should be either removed or have their added effect on breeding be removed. Just have a Munchlax hatch from a Snorlax parent without it having to hold an item.