I am in the same boat for, maybe a couple years now and thought I'd share what I did to avoid the issue:
1. underclocking: in Precision XOC (the version that supports this card) 70% power target (priority); 68C temp target (unlinked), gpu clock offset: -20MHz, Mem clock offset: -100MHz, fans at max all times (saved this as a preset, so I switch to something else without 100% fans when not gaming)
2. capping any game to 60fps max (negates the issue, running "stable" for years)
Desktop refresh rate may be kept at 165Hz, it only burns out when something demands 3D frames from the board. So maybe it's a mix-up with load + fps.
I am pretty sure the led that comes up is the D3909 one (VRM if tin's memory served him well), and it makes a lot more sense than the MCU firm one.
Side effects I have had here (that makes me believe it's not a PSU issue) are:
- I used to use a QNIX QX2710LED plugged to its DVI port. It's kinda hungry DVI port in the panel as it uses a passthru board and requires dual-link DVI.
- at some point the DVI port simply stopped working, the QNIX monitor never turned up signal on that port again (to solve that one, I plugged an old 670GT I had and use it as secondary video card; running smoothly for years); if was after then that the first D3909 light up event happened.
- I also had a VGA screen hopped to the KP thru an HDMI converter/adapter; now it pugs in native DE15 VGA port from onboard graphics (three display adapters for three monitors lol)
- When that happens, the system is still responsive; the game (probably, I can't see!) crashes, screen black, but keyboard interacts. I've bound the power switch for a single press and gracefully shutdown windows, and it goes as planned.
- After a while shut down, I can turn it back up and all is well -- except for some re-detection of the video card and rearrangement of desktop/windows
- If I turn it on immediately, the card does not initialize
- Sometimes boot up results in default screen elsewhere, usually 670gt, green dots in KP's display, and I can disable-and-re-enable in device manager to bring it back up.
I have just purchased a 4090 and I'll probably put the QNIX screen down, served me well for 13 years. I think I got unlucky with the DVI circuitry in the KP -- an exception among 1080Ti, perhaps the only 1080Ti with DVI -- and maybe it was not able/designed to handle stably passthru DVI for the long run.
Maybe now with the replacement board I gather the courage to debug the board. If I find anything I'd share here for well, posterity, I guess? :)
Too bad EVGA left NVidia world. :`(
edit: I just triggered the issue now playing American Truck Simulator, power cycled as usual, then updated the workaround to include the settled settings in (underclocking is mandatory).