For what it's worth. All good now on my end. Update is officially gone. I'm still going to say that it was just a "stuck" update that either installed but didn't clear out or was superseded by another bigger update and KB5018418 just stayed in the list for some damn reason. At any rate, for...
Well, I did some things and now the KB5018418 isn't showing up in the update list. I also tried to install it manually and the installer says that it's not applicable which lends credence to it already being installed. I think what may have been happening is that it may have actually installed...
On the off chance that you DO have errors, use the following to attempt to fix them: DISM /Online /Cleanup-Image /RestoreHealth
For more information about using DISM check out How to use DISM to repair local image on Windows 11.
(I'm actually waiting for something to finish installing/scanning...
DISM /Online /Cleanup-Image /ScanHealth does a very thorough scan. It also doesn't change anything. Just reports on any potential corruption. 😎
EDIT: But if the first quick scan came up good, you're likely fine. 😉
Also... I don't see anywhere that you tried running DISM. Just to be sure... Run the following from a command line to make sure you don't have any other problems: DISM /Online /Cleanup-Image /CheckHealth. It won't change anything; it will just report if your installation is healthy or not. 😉
Hold on! I'm trying some things myself... Don't do a repair install yet. I'll let you know what I find. I have the time today and I'm determined to squash this issue. TODAY. 😎