Wondering what the Install during automatic maintenance GPO is all about? Install during automatic maintenance is a new feature that’s available since Windows 8 and is not specific to WSUS.
Windows 8 and above have a feature called Automatic Maintenance, which detects when the computer is not in use and performs maintenance tasks, like defragmenting the disk and stuff like that. The Install during automatic maintenance selection of the Configure Automatic Updates GPO gives Windows 8 and above clients the option to install updates while Automatic Maintenance is being performed, if the scheduled update time has not yet arrived.