when you lose a battle
In English releases of the Generation II and III games and Japanese releases of the Generation II games and Pokémon HeartGold and SoulSilver, the player will instead white out; in English versions of Pokémon: Let's Go, Pikachu! and Let's Go, Eevee! and Pokémon Sword and Shield, the player will instead be overwhelmed by their defeat. Both of these are identical in function to blacking out.
The only difference is the color.
Source