Microsoft released the KB4476976 cumulative update for Windows Insiders in the Release Preview ring. It contains Action Center fixes for the Windows 10 Version 1809 release it pushed to customers on October 2. Microsoft also released new cumulative updates for Windows 10 version 1809, version 1803 and version 1709, as part of company’s monthly Patch Tuesday cycle. Users are already experiencing issues with some of the updates released January 8, which are behind networking and licensing issues according to multiple reports coming from both home and business users.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-releases-cumulative-update-kb4476976-to-fix-action-center-issues/