Microsoft's recent Windows 10 KB4512941 is causing issues with increased Cortana power draw. This update, which is a roll-up of security and bug fixes, was released late last month and users are complaining about Cortana's SearchUI.exe process constantly drawing up to 30-40 percent process load.
Interestingly, the bug was reported to Microsoft via the Windows Insider beta testing program, but it seems the software giant decided to ignore it:
It's not the first time Microsoft has been accused of ignoring feedback from its own beta testing programme: Windows 10 users were hit with a serious data-loss bug in October last year, prompting the company to pull the update and eventually re-release it for most users in November - but not without remaining issues.
Check Bit Tech for a temporary workaround to resolve the high CPU resource draw.