Microsoft released quality improvements to the Windows 10 version 1903 servicing stack. Microsoft says this critical servicing stack update addresses an issue with a Secure Boot feature update that may cause BitLocker to go into recovery mode because of a race condition. Windows Server users can use the Windows Server Update Services (WSUS) to mass deploy the update to all computers on a network. Windows 10 customers who experience issues while installing the latest updates can follow this guided walk-through with all the steps for fixing the encountered errors.
Source: https://www.bleepingcomputer.com/news/security/microsoft-updates-the-windows-10-version-1903-servicing-stack/