@danderson Two slight corrections: you can't ask for "standard 5V/3A", you only ask for 5V. The available current is advertised by the source with Rp (which has 3 options: either USB standard 100/150/500/900mA, 1.5A or 3A), the device does not ask for it.

Also, providing 5V on VBUS without Rd on CC does not violate the spec. USB-C sockets are not supposed to do that, but plugs can. Otherwise USB A to C cables would be illegal.