The information in this article can help you when Game & Watch: Super Mario Bros. wakes up from sleep mode while being charged to a USB port on the Nintendo Switch dock.
Game & Watch: Super Mario Bros. is designed to be charged via a USB cable. If the device is being charged using a USB port on the Nintendo Switch dock, the device screen may unintentionally “turn on” when the Nintendo Switch console is inserted or removed from the dock, or when Nintendo Switch communicates with the servers.
What to do
Charge the device with the USB charging cable and Nintendo Switch USB AC adapter
Connect the included USB charging cable to the device, then to then to a USB-compatible AC adapter (sold separately).
Connect the USB-compatible AC adapter to a wall outlet.