Dirac Issue - pre-amp not routing subwoofer measurement sweeps

I just added a second subwoofer to my setup (NAD C658 + NAD C298), and attempted to re-measure the room with Dirac.  I last used Dirac successfully in April 2025 when the room was in a 2.1 setup.

When launching Dirac it works as expected until you have to set the levels on the subs (prior to measurement).  The noise plays through the L+R speakers, but when trying to set the levels for the subs, no sound is sent, and the speakers are silent.

IMPORTANT: during the level setting, the noise that is sent to the main L+R speakers is also being sent to the subwoofers.  Dirac has told me that it should not be doing this. Again - when sending a signal to the subs to set a level, nothing is sent.

Attempting to measure the room fails, as the sine sweeps are never played through the subs, and Dirac throws an error that the signal to noise ratio is poor (obviously since there is no signal coming from the subs in the first place.)

When playing music / TV etc, the subs work fine. It just doesn't work in testing.

I've been attempting to work through this with Dirac support for a week, testing various setups to see if we can get it to work.  This includes:

• Factory reset of the C658
• Uninstall and clean reinstall of BluOS on Mac and iPhone/iPad
• Uninstall and clean re-install of Dirac Live
• Setting levels / measurement with one subwoofer only
• Connecting the microphone (Umik-1) to both the Mac and the C658
• Changing crossover frequency on the C658

Nothing has worked.  Seeing as how I can't even measure in a 2.1 setup (which I've done previously), something has changed in Dirac, NAD firmware or BluOS between April and now that seems to have broken the routing of signals when measuring in Dirac.

BluOS 4.10.19
MCU v1.63
LED v1.9

Dirac MacOS 3.13.13