Hey there, i'm facing a problem on my board. I've a GA-Z87X-UD3H, and have it flashed several times with moded bios from UBU with nno problem. Now maybe, if i'm not saying any mistake, and because i didn't saw the problem or even, i wasn't sure if the problem was always there the time i've bought the board. But here it is, i saw the problem after doing an ME firmware update, the real time clock date on BIOS setting count 2 seconds after 2, and in every 10 seconds only one time it will count 1 seconds. Let me be more clear:
17:21:2
17:21:4
17:21:5
17:21:7
17:21:9
17:21:11
17:21:12
17:21:14
17:21:15
17:21:17
17:21:19 and so on, but in overall, the clock from what i've seen, is sync with my phone and watch clock. The only problem is counting the seconds, and the minutes are still the same as worl clock. Which it means, that the RTC digital have a bug instead of counting one second after one, it count two seconds digitaly, and one after one analogically. Now back to my original ME firmware, still the same this happen, even flashing with downgraded bios or updated bios or from fpt, resetting the CMOS, these doesn't seems to solve the problem.

If you have any suggestion, i'll be very gratefull.

Yes i did, upgrade the motherboard ME Firmware until the 9.5 which i guess it was successfully flashed. Then tried the 10 and it said that it's n,ot compatible. Now i'm on the original one that came from GIGABYTE which is the 9.0.30.1482 H.
And here's the ME Info log:

Intel(R) MEInfo Version: 9.1.45.3000
Copyright(C) 2005 - 2017, Intel Corporation. All rights reserved.

Intel(R) ME code versions:

BIOS Version: F11c
MEBx Version: 0.0.0.0000
Gbe Version: 1.3
VendorID: 8086
PCH Version: 5
FW Version: 9.0.30.1482 H
LMS Version: Not Available
MEI Driver Version: 11.7.0.1045
Wireless Hardware Version: Not Available
Wireless Driver Version: Not Available

FW Capabilities: 0x41101960

Intel(R) Anti-Theft Technology - PRESENT/ENABLED
Intel(R) Capability Licensing Service - PRESENT/ENABLED
Protect Audio Video Path - PRESENT/ENABLED
Intel(R) Dynamic Application Loader - PRESENT/ENABLED
Service Advertisement & Discovery - PRESENT/ENABLED

TLS: Disabled
Last ME reset reason: Power up
Local FWUpdate: Enabled
BIOS Config Lock: Enabled
GbE Config Lock: Enabled
Host Read Access to ME: Enabled
Host Write Access to ME: Enabled
SPI Flash ID #1: C22018
SPI Flash ID VSCC #1: 20452045
SPI Flash BIOS VSCC: 20452045
BIOS boot State: Post Boot
OEM Id: 00000000-0000-0000-0000-000000000000
Capability Licensing Service: Enabled
OEM Tag: 0x00000000
Localized Language: Unknown
Independent Firmware Recovery: Disabled

If you mean by in bios flasher the GIGABYTE Q-Flash, i did it but the problem always there. About confusing, i do not update the driver only the firmware using the FWUpdLcl64. But as you said it could be a hardware issue, because the first time i've bought the board i remember that their was a circuit smell, like something burned, but no signs of that on the board. The board shutted down itself and reboot sometimes, before doing ME firmware upgrade. So maybe i've bought it with that problem, and i've expected that. I use two drives, one for Windows and the other with macOS Catalina then installed the Big Sur, and i've noticed in every reboot, the RTC clock get one hour less than the real time. And whatever patch i used to fis Device RTC, doesn't work, using Ozmosis, Clover or OpenCore.
Is there anything that i can do to solve that problem? Let me know please if you want more infos or something, if you know how fixing it, and thank you mate.

I'll leave it as is, as it doesn't bother me, and the performances are what i need while in gaming, better for me to don't do something and keep it like that, everything is correct except that RTC.
Thank you @plutomaniac for your help.