Microsoft removed a compatibility hold after fixing a known issue that would lead to Qualcomm Bluetooth radios having issues discovering and connecting to Bluetooth devices after installing or updating to Windows 10 1903. Qualcomm Bluetooth discovery and connectivity issue has been resolved with the release of the KB4517389 cumulative update. Microsoft provides a workaround for affected customers, advising them to check with their “device manufacturer (OEM) to see if an updated driver is available and install it. You will need to install a Realtek driver version greater than 1.5.0.0.”
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-removes-windows-10-1903-update-block-after-bluetooth-fix/