I discovered this seems to be a problem related to my own PC setup. I have a 2 display system and I usually run beaTunes on my 2nd display.
I discovered when I move a badly-displaying beaTunes non-maximized window from display #2 to display #1, the problem "goes away". In other words, beaTunes looks "right" on display #1 and "messed up" on display #2: same image.
I'll note that I've been having some other weird display driver issues on my PC this year, so I'm attributing this problem to my own unique PC and not a beaTunes issue. (Even though no other app of mine behaves like this, I still think it's something in my PC that is goofed up.)
Sorry to file what turned out to be a false bug report.