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:
THE SYSTEM HAS POSTED IN SAFE MODE.
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:
s10.postimg.org/l88ji4bl5/z37.jpg


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.

2 times, i turn off my pc for 12 hours,booted in morning, and fine again. But i want to be sure thats all is ok.
Memtest not showing errors also.
Really appreciate it for help. This is my new pc.

Don't Enable XMP. Set your memory speed, voltage and timings manually in the UEFI bios.

while setting manually is preferable, I wouldn't worry about this sisis, unless it happens again. If CPU-Z is showing your ram at the preferred speed you are ok now. Probably a BIOS bug or the mobo takes more than one boot to make the change fully or whatever.

Thread closed.

for further information to other readers - the opening poster has previously been banned and so is banned again.

We'd not normally ban someone who asked for help ;)...not normally anyway ;)