Since I upgraded to Paint.Net 5.0, every time I restore down after maximizing, the resulting window is 31 pixels taller (growing down). Doesn't seem to matter what (if anything) is loaded, nor where the Paint.Net window is, nor its starting size. Goes right off the bottom of the screen after a few iterations. Windows 10, dual monitors placed vertically. Not really a big deal, just kinda weird.
EDIT: It also happens when I restore the Paint.Net window after being minimized.