Halo MCC and Dinkum Xbox Controller and Instances Issue

Hey anyone please help - I've been using Nucleus Co-op for a couple years with no dramas, playing Halo MCC and Dinkum on my laptop and monitor (connected via HDMI) each with their own Xbox one controller connected via cable.

However as of Halloween I can load the game instances as per normal (one on each screen), but then with no software or hardware changes to my computer my instances only focus one at a time, with the other continuing to run just not being focused. On top of this both controllers can control that focused instance instead of being assigned to their own instance via Nucleus co-op setup like usual.

I have tried multiple threads on here and utilised HidHide for each controller, DS4 Windows (which I think was pointless as they were Xinput controllers already), Nucleus co-op client update, removed all controller software from the computer, disabled steam input for xbox controllers in big screen mode, Installed and configured Xoutput for each controller and finally reinstalled the handlers for each game.

Any further advice or suggestions would be greatly appreciated please.

PS Love Nucleus co-op btw, it allows my partner and I to play games together without buying another computer so thanks Nucleus team, You're amazing!