Microsoft incorrectly pushed KB4523786 to some users
Microsoft recently pushed multiple cumulative updates to Windows 10 Version 1903, which have both fixes and alternative updates. Interestingly, there is an unsolicited optional update in addition to these cumulative updates, which Microsoft pushed to some users due to certain errors.
The Microsoft Update No. KB4523786 optional update is actually a cumulative update to the Windows Autopilot system. This update does not apply to regular users. Although there is currently no evidence that users will experience compatibility or other failures after installing this update, Microsoft has issued an announcement reminding users not to install. If the user encounters this optional update, users can directly choose to ignore the download without installing it, so as to avoid some potential anomalies after installing this update.
Via: mspoweruser