'Slow Charging scenario':
When the USBC-7N1E adapter is 'passing through' power from an external USB-C power adapter to the host laptop, a small amount of power from the USB-C power adapter is used in order to power the USBC-7N1E adapter itself.
The net result is that the amount of power provided to the host will be slightly less than the full power provided by the USB-C power adapter. Depending on power thresholds set by the laptop manufacturer, this may result in a warning that the system is charging at a slower than expected rate.
'No Charging scenario':
If the USBC-7N1E adapter is connected to the host laptop without a USB-C power adapter attached, the USBC-7N1E adapter will draw power from the laptop in order to power itself. If an external USB-C power adapter is then connected to the USBC-7N1E, the laptop may not start to charge.
This is because not all laptop models will reliably 'switch' the flow of power. Should this occur, simply disconnect the USBC-7N1E adapter from the host laptop. Once disconnected, connect the external USB-C power adapter to the USBC-7N1E adapter and then connect the combined assembly to the laptop. The laptop should now be charging.