Hi Arakasi
Many thanks for your reply.
I understand it appears difficult to diagnose at first glance. However, IBM SPSS Statistics triggers Presentation mode as it loads allowing you to see the yellow exclamation mark on the tray icon (hence I am certain Gamer mode is not activating itself on NOD32).
I have another ThinkPad with Endpoint Antivirus, so I could actually get that screenshot if you need it.
I have not had a chance to look much further into it yet, but it does seem NOD32 continues to update itself. It never updates itself upon exiting full-screen as it is already up to date.