I have a Windows 10 Pro computer on my domain that rebooted last night automatically. It appears that Windows update initiated the reboot. However, I control updates through WSUS and group policy. The GPO setting is to "auto download the and notify to install" updates (Configure Automatic Updates). I verified that this setting has been applied on the client by looking at the advanced options in the check for updates page.
Here is the event from the client that initiated the reboot.
Event ID: 1074
The process C:\WINDOWS\system32\svchost.exe (client-name) has initiated the restart of computer client-name on behalf of user NT AUTHORITY\SYSTEM for the following reason: Operating System: Service pack (Planned)
Reason Code: 0x80020010
Shutdown Type: restart