The way USB-C works with adapters to legacy USB (USB-A and USB-B) is brilliant. Unlike in USB-C, in legacy USB the power roles are fixed: the USB-A socket and U

The way USB-C works with adapters to legacy USB (USB-A and USB-B) is brilliant. Unlike in USB-C, in legacy USB the power roles are fixed: the USB-A socket and USB-B plug provide power (source), the USB-A plug and USB-B socket receive power (sink). A USB-C to legacy adapter always has a USB-C plug (never a USB-C socket), and one of these four legacy alternatives. If the legacy end of the cable is one which receives power (USB-A plug or USB-B socket), the USB-C end has a pull-up resistor to that power on the configuration pins, indicating to the USB-C device that this cable provides power; if the legacy end of the cable is one which provides power (USB-A socket or USB-B plug), the USB-C end has a pull-down resistor to ground on the configuration pins, indicating to the USB-C device that this cable requests power. The USB-C device only connects its power output to the socket when it sees that pull-down resistor, so the power supplies will not be shorted together if the cable always provides power to it. And the only thing necessary for an adapter, or for an USB-C device which only receives power, is a pair of resistors. And this explains your scenario: in the USB-A plug to USB-C plug case, the cable always provides power on the USB-C plug; in the USB-C to USB-C plug case, the device on the other end will only provide power when it sees the pull-down to ground, which should be provided by the device, and in your case is probably missing.