Avoid installing KB4512941 for now if you have already disabled the Web search functionality within Windows Search (BingSearchEnabled registry key set to zero to disable Microsoft's intrusive search behaviour).
After installing the update I noticed that my 3600X was no longer downclocking and the processor core voltage remained stuck at its maximum, with taskmanager showing Cortana stuck at 13% processor usage and clearly the culprit.
The Windows Search box will still pop if you click on the icon, but is no longer functional.
Looks like a Microsoft bug (intentional or otherwise), and plenty of discussion about it already:
https://www.ghacks.net/2019/09/02/c...windows-10-1903-update-reported-to-microsoft/