Latitude 9420 2-in-1 "Time-of-day not set - please run SETUP program" error at every boot on the battery power

Hi DELL Community,

Details of the device in question:

Latitude 9420 2-in-1 is on the latest version of the BIOS - 1.38.0, 1.38.0

Running Windows 11 Pro - Version 24H2 with the latest 2025-05 Cumulative Update Preview for Windows 11 Version 24H2 for x64-based Systems (KB5058499)

Laptop has the original battery fitted in, holding the charge (70% of original capacity left), battery is reporting as "Excellent" condition in the BIOS.

There is no CMOS battery on the motherboard. 

Issue:

If you shutdown the laptop with no charger plugged in, upon the next boot you will see the "Time-of-day not set - please run SETUP program error" and the Real-Time Clock stops working immediately.

Issue could not be reproduced if you shut down the laptop and leave it on charger, Real-Time Clock (RTC) continues to work.

Any ideas or KBs to try would be appreciated.

Many thanks!