So I'm currently working on a little side project contribution where Pokemon that are caught in previous generations have an Origin Mark that can be displayed in the current games to show their respective generation that it was caught in. So for example, a Mewtwo that was caught in the Virtual Console games of Red and Blue can be transferred up to Gen 8 and display a GameBoy Icon representing that it was caught in Gen 1. A list of all Origin Marks can be found here https://bulbapedia.bulbagarden.net/wiki/Origin_mark . There can also be Pokemon like Sylveon or Alolan Exeggutor that can have those Virtual Console Origin markings, despite being in Gen 6/7 games, as they can be traded up and evolve in those games.
Now for the issue. According to that Bulbapedia website posted above, the Let's Go Pikachu and Eevee games have their own origin marking, representing a Pikachu head. After downloading a living dex from those games here:
All the origin markings are shown as being from Alola (Black Clover Symbol), which is impossible, instead of having that Pikachu head. However, according to that website, "Although it is not displayed (origin mark) in Let's Go Pikachu/Eevee, it is displayed is Pokemon Sword/Shield". So I decided to drag and drop these Pokemon into another PKHeX window with Sword and Shield loaded, but it still pops up as being from Alola instead of the Let's Go games.
Furthermore, with Pokemon GO now being able to be transferred, it is shown in that website that those mobile Pokemon also have an Origin Mark, representing a G. So I did some further testing and downloaded a Pikachu file that was caught in GO and put it into PKHeX here:
Same problem occurs where it is shown as being from Alola instead of the mobile game.
Just thought I would point this out since it is a bit interesting.