SCCM 1806 KB4459354.

After the WDS-less PXE responder service is configured after an upgrade to Configuration Manager 1806, it may reject PXE-boot requests from clients when the management point (MP) is remote.
Task sequences that have a restart action before an Install Packages action may fail. Error messages that resemble the following are logged in the smsts.log: Query = ‘CCM_UUPPSFXConfig.SiteSettingsKey=”1″‘ … WMI error reading policy, hr=0x80041010 … Class CCM_UUPPSFXConfig does not exist in name space ‘root\ccm\policy\machine’ because client has version of
Unable to delete a secondary site. After the deletion action, the site remains in either an “active” or “deleting” state.
CMPivot cannot run a PowerShell script that contains a command to retrieve a registry entry if the registry contains a NULL value.