Pokémon

I guess that’s just Game Freak’s way of dealing with Pokemon having different move pools in different games.

To put in more detail, basically Pokemon Home keeps track of a Pokemon’s move set for each game. When a Pokemon is transferred to a game it has never been to, it will get some default moves (last 4 level-up moves?) and Home also let you relearn level-up moves during the transfer. If a Pokemon is transferred to a game it has previously been to, its move set will automatically switch to the move set it had before leaving that game.

It kind of make sense if they want to control learnable moves in each game and eliminate moves only obtainable through other games. The real sad thing is old gen’s distribution/gift Pokemon will lose their unique moves forever, because Bank to Home is a one-way transfer.