I've noticed a minor bug where the secondary screen will get stuck on its immersive mode, showing the clock, signal strength, and notification icons. It'll stay like this even when on your home screen.
So this tip is how to reset it.
Chances are, you had been in a full screen app, like a game or the photo gallery, and exited in a non-standard way. I.e. You used the home button or recent apps button to switch instead of using the back button or the app's dedicated exit functions when available. What you need to do is go back into that app and then fully exit it rather than simply sending it to the background.
This bug doesn't always pop up in my experience, so it could perhaps be a lack of optimization on the app rather than a bug of the V20 itself. I've also noticed you have to use the original triggering app in question. If it was a game that triggered the bug, viewing a photo in the gallery and then exiting from it will not work. You have to go back into that game and then exit out from it.