Windows 10 (1903) PC keeps waking up from sleep on its own.
powercfg -lastwake shows that PC was woken up svchost.exe (SystemEventsBroker) to execute Universal Orchestrator Start scheduled task. Presumingly this task runs Windows Update, which would be fine if PC was put back to sleep afterwards. Unfortunately, this doesn't seem to happen and PC stays awake.
Disabling "Allow scheduled maintenance to wake up my computer at the scheduled time" which previously fixed a similar issue on Windows 8.1 doesn't make any difference.
In this case, the issue was resolved by disabling Allow wake timers in Advanced Power Options.
Windows 10 Pro (1903)