It's documented at https://support.microsoft.com/en-us/help/4088776/windows-10-update-kb4088776
For now you either call Microsoft for a fix or wait till it's fixed. There are others asking but this one is all Microsoft to fix. I would not waste one more minute on this one. But there are folk that will make the call.
For over a month (early April 2018), Win10 Updates claims that I need to install KB4088776, a cumulative update. When I try, it calls for a restart. However, each time I try it restarts itself several times then states that it could not complete and is undoing changes. This also happens whenever I do a manual restart. Eventually it gets to a point where I can log in to my desktop but Windows Updates still shows that this update needs to be installed through a restart. Windows Defender Security Center also shows this issue as a problem under Windows Performance and Health. Currently running AVG (paid) and CCleaner Professional on an HP Pavilion a6658f.

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