XMP - system post in safe mode. Happened once after some time pc off

Hi. My mobo is Asus Z370 Pro Gaming. And rams: Gskill 2x8GB 2133mhz ( XMP 3000mhz ).
Cpu 8700K. When i choose in UEFI first time XMP profile i saved and booted fine to UEFI.
I turn off pc,turn on again after 2 hours, and then, i met screen:
This happened just once. Now its booting fine,but i dont know why it booted just once with this message.

This is screen from internet ( not my pc ) ,but the same msg to show:’

I tried to reproduce this warning but i am not able to do that. Reverting to standard and then again to XMP save. Turn off pc by power button. But not warning. Any ideas why it happened just once,and still its something wrong?

This occured when pc was off some time , 4 hours . And then. I met users using XMP with the same issue , only after pc was off some time.

Memtest not showing errors also.

Really appreciate it for help. This is my new pc.