Check that you've not got your NI Audio 6 set to be your default Windows sound device.
Windows has a nasty habit of stealing USB audio interfaces after an update, and forcing the audio format to what it wants.
If this is the issue, you've got two choices:
1. Set the audio format to what you want within Windows to match what you want in CbB; or
2. Set your Windows sound device to be something else like the in-built soundcard on your motherboard (which is the better solution)