I don’t use Windows.
And I don’t use Impress.
With those two things understood, I wonder if what you’re experiencing is what also has happened to me on Mac, and using Keynote. My (occasional) problem is not in the operating system settings. It’s not even, in Keynote at least, in the preferences of the application.
Rather, on the screen that is monitoring the presentation (but should be showing the presentation), there is a sub-menu which, amongst a couple of other things, allows the operator to control which screens display the different things that you want displayed. BUT …
That sub-menu (again, on Keynote) appears when the mouse cursor is moving. And it disappears shortly after the mouse has stopped. You have to be quick!
As I said, I don’t use the same systems as you do, but my symptoms occasionally match yours. It might be worth investigating.