Hello PeterJ,
I ran a Disk Cleanup and deleted 4.6GB of "Windows Update Cleanup". Then, when I shut down the computer it did install some "update cleanup", then again when I started the computer.
Now the Windows Update is not proposing KB4038777. It proposed and installed some other updates. It did not mention KB4038777.
But now it keeps installing KB4041083 and KB4043766 over and over again. The result of these updates is always "successful", but it keeps asking to install them.
Any clue?