Yeah, I think I've found the issue.
In "Windowed" mode for 1920x1080, it keeps the windows bar (40px?) at the top, which extends the 1080 off the bottom of the screen by the same amount.
This is fixed by using the Maximized Window or using a lower resolution from the Solasta option.
So this is pretty much resolved, unless they wanted to render it at at 1920x(1080-40px bar), which seems unnecessary.