It happens because the security directive "Interactive logon: do not require CTRL+ALT+DEL" defined on your domain's GPO is activated. By default it's not activated, so the network administrator activated it. Because of that, when the machine is restarted, the screen demanding Ctrl+Alt+Del is not shown and this screen should be the Griaule Logon screen. Because of that, it's necessary that you press ESC key (or try to log in) to return to Griaule screen.
Solution
Disable this security directive on your domain machines. This directive is available on GPO at "Computer settings → Local directives → Security options → Interactive logon: do not require CTRL-ALT-DEL". The "right" setting for this is to set it as disabled, increasing security, since it ensures that a Ctrl+Alt+Del key combination redirects you to your Windows Logon screen. After that, the first screen to be shown on machine reboot will be the Griaule logon screen.
