Weird BIOS Reset/No Post

Hi @all, first a little sorry for my bad english...

There is a weird behaviour of my ITX System and i hope somebody can help me System: ASrock B460M-ITX/ac i3 10100F 8GB GSkill F4 2400C15 RX6400 LP

First time boot was fine, configured UEFI, reboot, everything works.

But... If I disconnect Power, reconnect it and Push the Power Button nothing happens. I have taken the Board out, and when i touch it here and there ist suddenly starts. UEFI is then resetting to factory settings, after doing my settings everything stays fine until the next time i unplug power.

CMOS Battery seems to be fine, 3.034 Volts. I ordered an new one anyway...

Does anybody have an Idea or explanation for this really weird and annoying behaviour? Liebe Grüße aus Deutschland.