X670E PG Lightining stuck on boot when restarting

Hello guys.
I have a strange issue with my system since I got it two months ago. I have been waiting for new BIOS versions to see if they fix this, but so far using the latest beta (1.14) I have the same issue.

Basically, when I restart my system, it will be stuck with CPU/DRAM led on and it won't go past that even after several minutes. First I thought it was the XMP settings that were causing this issue, because they keep being reverted to 4800MHz when that happens. But I noticed that even with default BIOS settings, upon a restart it can get stuck on that was well after a restart.
The strange thing is that if I manage to apply XMP settings and I DON'T restart, the system is fine and the RAM keeps its XMP settings and the boot is fine. As soon as I restart it gets stuck and I have to force shutdown or clear CMOS.

I have tried increasing every possible voltage, disabling Power Down Mode, several different settings and nothing helps.
I have tested each of the RAM sticks and they are fine.
The system is perfectly stable at XMP settings when running stability tests or intensive games and I only shutdown and don't restart.
I have reseated the CPU to check for bent pins, everything is fine.

Note: sometimes when restarting it will not be stuck with leds on but I notice that the system shutdowns and then starts again (because of the power supply "click" sound). When it starts up again, if I go to BIOS, the XMP settings will be "saved" but the speed is not applied and will be 4800MHz.

Any help will be appreciated. Thanks.

Motherboard: Asrock X670E PG Lightning
RAM: G.Skill F5-6000U3636E16GX2-TZ5RK
CPU: AMD R7 7700X