When we access the console we go through vSphere Web Client versus the NoMachine windows client.
Installing 4.2.x on the server effectively makes it so you cannot Log Out of your GNOME session, this is true if we use vSphere Web Client or NoMachine Windows client ( 4.1 or 4.2 ).
Going back to 4.1.x on the server eliminates this behavior and all works as expected.
Again there are no errors in any logs, we simply choose to Log Out of the GNOME session and the buttons in the dialog image I sent you [Cancel and Log out ]are not enabled OR do not respond to a mouse click. All we can do is hit the X in the top right to forces a termination of the dialog.
As there is no way to Log out of the session we must use nxserver –terminate to kill the session(s).