Nighthawk M3 MH3150 and Ethernet Adapter - USB-C input does not charge battery

I have a Nighthawk M3 MH3150 and a Netgear Ethernet adapter.

(The M3 has no ethernet port, just a USB-C one, so needs the adapter for ethernet).

The adapter has one 'in' port USB-C to connect to the M3, one 'in' port for USB-C power-in, and one 'out' port for ethernet.

When I plug in the adapter, ethernet works fine.

BUT the 'in' port for USB-C power-in does not keep the M3 charged.

The lightning charging on the M3 battery icon does not appear.

I have tried many, many different USB-C power sources from 10W to 60W and still no charging.

Does anyone use this setup?

Is there some obscure config setting I need to change somewhere to get this battery charging active?