It just seems weird to me that Nintendo would add a check for known homebrew files (or some similar basic homebrew detection) to a *Pokémon* update. If I were a multi billion dollar company, I'd probably prefer to keep code that has nothing to do with Pokémon out of my Pokémon codebase. On the other hand, it's quite easy to "accidentally" send telemetry data containing information on homebrew apps to them. I'm honestly surprised it took them so long to ban for that, if it does actually turn out to be the reason. They have to maintain a list of legit title ids, so it's trivial to spot homebrew.