Question PC losing power but only when restarting or exiting BIOS

Jul 8, 2020
See title. What can I do about this, and more importantly, should I be doing anything about this? After all, I've used the PC for 4 months and it has been 100% stable, as long as I never restart it or tinker with BIOS.

To clarify: I can shut it down and start it back up with no issues. Only when I use the actual "restart" option in Windows, it loses power multiple times in a row and then posts to safe mode. The same happens when I exit BIOS. I can bypass this by pressing the power button to shut off the PC and then start it again, this removes the safe mode post and starts the PC normally. But it is quite annoying, knowing that something is still not right with my build. Any suggestions?

FWIW, the specs are:

mobo - ROG STRIX X570-E
cpu - Ryzen 7 3800x
graphics - ROG STRIX RX Vega 56
memory - Corsair Vengeance LPX 2x 16 GB
psu - Corsair HX750i