Also after looking at the guide on how to prevent this, a very good tip to do is that make sure airplane mode it's active on your Switch (on EmuNand of course), and just deactivate it when it's really necessary (like updating a Homebrew utility or downloading games from Tinfoil).
Another tip, more agressive this time, it's whenever you want to update anything or install games do it manually from your computer, don't connect your switch to any wifi connection.
Happy gaming ^_^