Nintendo has said that it is currently in the process of investigating errors that have been reported by users playing the GameCube game Pokemon XD: Gale of Darkness on the Nintendo Switch Online service. The news was shared by the Kyoto-based company’s customer service account on X. Nintendo says that it will notify fans as soon as there are any updates and politely asks them to “please wait a little longer.”
We are receiving inquiries regarding errors that cause the game to forcibly close while playing *Pokémon XD: Gale of Darkness Dark Lugia* from *Nintendo GameCube Nintendo Classics*. We are currently investigating a solution. We will notify you as soon as there are any updates, so please wait a little longer. Please note that if the game forcibly closes during play, save data will not be saved. Therefore, please use the “Quick Save” feature in the “Pause Menu” within the game. We sincerely apologize for any inconvenience and trouble this has caused.

I know emulating GCN games on the NSO isn’t easy but I’m guessing something went wrong in running the game? Either way I’m glad they are trying to fix it. It would also explain why we barely get GCN drops, doesn’t explain the other consoles though.