My Copy of Dragonfall does this most times it starts up. It's not a complete blank, because if you put the mouse over the black area, the mouse is still visible. Additionally, it's not just the menu. If I start the game before it goes away, the loading screen will have the same bar at the top.

Specs
Windows 10
Graphics: NVIDIA GeForce GTX 1660 Ti
Processor: Intel® Core™ i7-9750H
RAM: 16GB
Storage: 512GB (2x 256GB PCIe M.2 SSD), RAID0

Screenshot won't attach.
Here:
https://photos.app.goo.gl/oy2htpjmMTxp2cD69

I have a similar configuration and a similar anomaly —— though it is completely harmless. In my case, the menu is scaled up, but the mouse active hotspots are fixed for the smaller text (or vice versa, cannot be bothered to check right now). I do not have the blank area above, however, and it doesn't affect any other part of the game.

It didn't happen before this monitor (Full HD 1920×1080), when the game scaled down to fit an almost-HD monitor (1600×900px), which also forced the rendering engine to zoom in on the scenes.

At a guess, I'd suggest it is an incompatibility between nVidia GPU and the monitor, therefore (in my case: definitely) that would be fixed by a driver update (eventually).

Does this affect anything in the game —— i.e., besides the static backgrounds? If not and in any case I expect the problem is driver-based and only will be solved when nVidia refresh their drivers.