New build with RM850x, it works fine apart from a weird startup behavior (post delay? short circuit?)

[rayarxios]

Hello!
So, I built a new PC with Corsair RM850x PSU - it's been working fine for few days apart from one weird issue that doesn't happen on my old rig (old rig doesn't use corsair PSU - sold it already).

Video on the Quirks/Issue:

When I press the power button, the pc sort of starts up then abruptly turn off (?) then it starts normally after that (can hear a tick/click sound on the psu upon starting normally) - you can see on the video that the ram RGB sort of flashes, and the fan sort of spin, stops, and then spin again and then it works fine. This also happens when waking up from sleep state.

This bothers me a bit as my old rig immediately boot upon pressing the power button - It's working fine for now but a bit worried about its reliability on the long run.

Things I Did:
- Reset BIOS
- Clear CMOS
- Update BIOS
- Swap RAM
- Barebone Test

Specs:
Gigabyte B550M Aorus Pro-P
5800X3D
TridentZ Neo 3600 CL16
Inno3D RTX 4070 Ti (Tried with older GPU, same weird quirks - so rule out the GPU)
Corsair RM850x
Crucial P5 NVMe

Probably defective PSU? or something else?

A help will be greatly appreciated!

[Corsair Notepad]

We would recommend you contact our support team directly by opening a ticket at https://help.corsair.com