Random thought just in case. I had this issue before as well and ended up resolving it through a BIOS update. I found that weird because same BIOS was working before (literally same boot). The Arch Linux post from kriestof linked to earlier shows that it’s related to some internal state, which in their case was at some point restored by running another OS. The topic got bumped again by kriestof last month with BIOS/firmware being significant once again. Any chance you can reinstall the latest BIOS (which I assume you already have) to see if that helps?