I see details about Intel HDMI audio vs Intel HD audio here…
I think this is a feature of the new Linux kernel. The old one seems to have depended on Intel HD to make the HDMI work. You were able to disable HD audio in the past, which broke HDMI support. They seem to have eliminated that requirement now. I don’t think you can actually disable HDMI audio in the BIOS, just “HD Audio”
We should move this conversation about HDMI and Intel HD audio here: