Grey box on secondary monitor

[dinghammer]

My primary monitor is 1920x1080, and my secondary (to the right, aligned at the top) is 900x1440 (it's in portrait mode). When I start the game (choosing "Play Halls of Torment"), it seems to start normally on my primary monitor, but then it jumps down and to the right (partially into my secondary) before returning to my main monitor and leaving a grey box behind where it had been on my secondary, in front of anything that may appear on that monitor.

If I change focus by clicking outside the game, it moves back to that position across both monitors, and when I click back into the game, it leaves behind a box containing whatever was visible in that area at the time.

If I turn off fullscreen, it goes back to that position, and I can drag it fully onto my primary, but when I turn fullscreen back on, it doesn't actually go back to fullscreen -- it stays windowed but just expands to go behind my taskbar also, and I can still see a few pixels of my desktop on each edge.

The only way I've found to prevent this and play in fullscreen is to turn fullscreen off, exit the game, restart it, and switch back to fullscreen. This is tedious, especially if I forget to turn fullscreen off before exiting the game.

It almost seems like the game is trying to center itself across both my monitors, but it's too far to the right and too far down for it to be properly centered, imagining a 2820x1440 canvas.

This bug also occurred in the demo, but I was hoping the full version wouldn't have it.

This also happens when starting with "Force Dedicated GPU", but it doesn't happen with OpenGL.

My GPU is a GTX 1660 Super with the latest game ready drivers on Windows 11. The game seems to run normally otherwise, and I haven't yet tested how much worse performance is with OpenGL.