This issue has recently started on my five year old PC. Running Windows 10 Pro 2004 19041.0 it has never previously had this issue.
Running powercfg /requests the only thing listed having power requests: [PROCESS] \Device\HarddiskVolume4\Windows\System32\MoUsoCoreWorker.exe USO Worker
Not sure of the relevance but did seem to coincide with installing:
2020-10 Cumulative Update Preview for.NET Framework 3.5 and 4.8 for Windows 10 Version 2004 for X64 (KB4580419)
2020-10 Cumulative Update Preview for Windows 10 2004 x64-based systems (KB4580364)
Windows Update stated it was up to-date but MoUsoCoreWorker.exe USO Worker was consistently showing up.
I restarted the Windows Update service and re-ran Windows update and it offered me KB4486712, then stated it was up to-date.
However cycling through restarting the Windows Update service and re-running Windows update another four times, it offered me one by one KB4486680, KB4484397, KB4486710, KB4486720.
Windows Update now stating it is up to-date and MoUsoCoreWorker.exe has not shown up for a couple of days.
Will see how it goes but to me does appear to be some sort of issue with Windows Updates getting stuck. Will post an update after a couple of weeks.