Tried today using Bluetooth with the RS250.
Normally I’m using with the RS250 an external USB-DAC.
Starting in such a configuration, it plays, but no sound comes out (also in using the headphone out).
Changing the output to analogue out brings the sound back.
This is for me a bug.
In general: It seems, that not possible to use an external digital source (usb or spdif in) with a digital output.