UI Button on Display 2 doesn't work (since 2021.3.xf1) with new Input System.

I have 2 cameras outputting to 2 displays. Each camera is attached to a canvas (Screen Space - Camera) with a button on it. If I build and run the application, I can see the two buttons on the two seperate displays, but I CANNOT click / interact with the button on the second display.

This seems to only be a problem with 2021 onwards, as it was working correctly in my current 2020 Unity Editor version. I have tried it on the following versions: 2021.3.0f1, 2021.3.8f1, 2021.3.9f1. Without success. It does however work on 2020.3.32f1 & 2020.3.38f1

Please note, I am using the new Input System.

I am having a similar issue of buttons not working correctly since upgrading to 2021 LTS versions of the Unity editor. However when the app is full screen, the buttons seem to work correctly, but when the window is not full screen some buttons are totally non functioning or shifted in screen space (in a cluster of UI buttons, the seems shifted downward, so the buttons don’t match)