Thinking out loud about this:
I have just seen this issue on the STRIX 3090 as well. Weird part is it seems to be working fine despite the lights. I am sharing this information because I am wondering if there is a micro spike during waking from sleep or initial powering back on the system that causes the red lights. I was talking to someone at the EK suite this CES with another 7x RTX3090 workstation and was mentioning how a lot of the 1600watt PSU they tested would fail the initial peak because the PSU could not respond fast enough, they only use Corsair and EVGA PSU because of that issue.
Wondering how many of these red lights can be from poor house electricity? I run this system below behind power conditioners and I have seen this red light flashing issue too so not sure.
Don't hate, it is a legit Octane render system but I have four RTX 3090 on one EVGA P+ 1600 (PSU2), three are STRIX black 3090 and one EVGA FTW3 3090, only two flashed but seem to be working normally. The same system has three other white STRIX 3090 on a different 1600watt (PSU1), those were ok. Going to check the GPU BIOS and see if anything comes of this.
One interesting thing to mention, each PSU is behind a tripp lite 1800watt power conditioner as well. SOMETIMES when flipping the switches on the PSU into the on position, the power conditioner on PSU 2 (one with the 4 GPU only) will click to step up voltage. COULD be because that one is on an extension cord into another circuit in my home though. That said, with GPU all set to 80% power, it only draws about 1300-1350watts, 90% about 1450watts, 100% was at 1590watts so that was too close for comfort to finish testing there.
Another interesting thing, I had a defective PSU originally in the PSU 1 position which is motherboard and 3 RTX 3090, that one popped when the system was booting after an initial benchmark run, the PSU was only pulling 1200watt too during the benchmark. I would need at least an analog meter to see any voltage drops and such. These digital ones aren't fast enough.
AMD 1100T 4255mhz
Asus Crosshair V formula
kuhler 920 modded for 2x120 radiators
corsair dominator gt 4x2GB 1866mhz 9-9-9-24 2t(stock)
msi gtx560ti twin frozr ii oc edition
corsair gs800 psu 800watt
corsair f120ssd series2/seagate 1tb 7200rpm hdd
rosewill blackhawk case - Asus cd/dvd burner
win7 pro 64bit - 1920x1080 display