After upgrading the DDC to 1912 CU5 the scheduled reboot only works approximately 50% of the time.
Issue was not seen with CU4.
This type of error is seen in the event log.
The Citrix Broker Service has completed the processing of the 'GroupReboot' for 'xxxxxx'. The reboot cycle (UID = '10591') successfully completed. Summary: '0' machines successfully rebooted, '0' machines failed to reboot, '0' machines were not processed.
The issue is observed when the VDAs are not power managed i.e. when there is no host connection defined to the hypervisor. This is usually the case with machines created by PVS or another imaging technology and then manually added in Studio.