Avid HD Native thunderbolt box’s headphone jack doesn’t output audio. Anyone have a fix?

On my HD Native Thunderbolt box there’s a headphone jack with a push knob to control the volume and mute of a pair of headphones. It was my understanding that the output mimics channels 1 and 2 of the HD Native but it doesn’t give any output at all. I plug the same headphones into the HD Omni headphone jack and there’s audio. Any idea why?

PT Ultimate 2023.6.0

macOS Sonoma 14.6.1

Avid HD Omni and HD Native Thunderbolt

Tried resetting MCU, unplugging and replugging, restarting multiple times, different earphones