Ever since the firmware update 5.0.0 hit for the Nintendo Switch, a lot of users have been complaining of bricked systems—which ultimately, it turns out, seems to be rooted in their usage of unlicensed third party docks (as opposed to the standard one that Nintendo sells, or licensed third party ones).
While the problem seems to have been alleviated to some degree by 5.0.1 that became available recently, Nintendo has warned against using unlicensed third party products and accessories for the Switch in a statement to Kotaku, noting that they aren’t tested for full compatibility with Nintendo systems and official accessories.
Which makes sense, of course—generally, even if you’re buying third party products, you probably want something that’s been approved by the official manufacturer, or you always run the risk of something like this happening. Hopefully, people with bricked Switch systems can get their data recovered and systems restored soon.