This is what I get when I include the flags:
wasapiNotifyProc: WASAPI device: 22 (Line-Level:1-2 (OCTA-CAPTURE), flags=BASS_DEVICE_DEFAULT), BASS device: 4 (1-2 (OCTA-CAPTURE)), notify: The device has been disabled/disconnected.
wasapiNotifyProc: WASAPI device: 23 (Line-Level:1-2 (OCTA-CAPTURE), flags=BASS_DEVICE_INPUT|BASS_DEVICE_LOOPBACK), BASS device: 4 (1-2 (OCTA-CAPTURE)), notify: The device has been disabled/disconnected.
I guess this is because the Octa-Capture does have both inputs and outputs, so presumably device 22 is the output device for the Octa-Capture's channels 1-2, and device 23 is for the corresponding input pair.