CMOS batteries should last around 5 years, so I'm not certain that's it.  I would suggest replacing one of them and see how it behaves.  I did have Sony batteries last me only 2 years. Also, when do the settings change?  Do they change after booting into OS, then shutting down, then check the settings in BIOS?  Then it might be the software.  Just changing the time in Win10, or any Windows I know of, changes the time in BIOS  If none of the above, it might be time to change the password, especially if it's been the same for the last 4 years, around the age of the machine.  You may know, more frequent password changes are generally recommended.
Hello, We have several optiplex 3060's that forget the Power Management settings. Settings like Deep Sleep Control and WOL settings. I am not sure what triggers this. BIOS is password protected so no one can change it. All other settings are retained when this happens. Is this a bug? Has anyone else encountered this issue? Thanks!
Dell 3060 not remembering Power Management settings