I have an NVIDIA QUADRO K2000 on a Linux Ubuntu 18.04.2 server and I get no audio over DP/HDMI.
Both DisplayPorts outputs are plugged and the /var/log/Xorg.0.log proves that both displays are recognized and their EDID information seems correctly retrieved.
Despite the above, the eld#0.1, eld#0.2 and eld#0.3 (from under /proc/asound/Nvidia/) reflect that no monitor was detected:
Exact same hardware/software setup using an Nvidia P2000 card correctly outputs the audio over DP/HDMI.
nvidia-bug-report.log.gz (2.77 MB)