Hi David,
yes, I think the USB-C hub needs to be powered (from external USB-C PD adaptor) to be reliable.
There is another connection method that works : USB-type A to USB-C cable. And this cable works for unpowered USB-C hubs that provide a USB A type port.
The USB-C connection can supply power to Moku:Go’s that are configured with firmware 543 from the factory. We have noticed that some of the early evaluator units do also work once upgraded to firmware 543. For all Moku:Gos, the PPSUs (programmable power supplies) can only be used when the magnetic power is connected.
PaulC