So I have had this setup since Alder Lake was released with a 12900K a Z690 Gaming A and an RTX 4090.
Last night I noticed the White Led was solidly lit during normal use after the machine was booted ie all checks passed during boot the leds went off after post and then an hour later the White Led came on the motherboard.
I did not notice any weird behaviour and all is normal, All I did was reboot and went off and hasn't come back on since, I don't if this is due to 1 of the 2 recently released bios's for this board or some other weird issue.
nothing to be concern. That happens when turn on the pc OR restart, from that point to post process the monitor goes to sleep or is sleeping after some time if inactivity. That can NOT be fix.
What you can do that i have done for YEARS, is to play with monitor osd. DO not select anything just to make the mointor wake or on at the moment of the post. that is it. sadly there is nothing we can do for that unless the gpu makers push a update for it. I have try to use, check other pc and in the does not work, does not work complete or return on the same.
I have try the nvidia solution, does not work on my gpus and as today maybe the one for the founders on the founder trent to work time to time. Is not a bios thingy.
It's just weird that I have never seen this issue before only since the latest last couple of bios updates and nothing of my hardware has changed, Using HDMI, Same screen same everything.
However it still hasn't done it again since so I have no idea what it was.