@degen
There's a chance that it's related to exact colors and the way Dasung handles area refreshing after something moves. Could you try to make screenshots of images that cause dithering on W10 to test them on W7 and vice versa? This way we'll see how both systems behave on the same entry colors. If it proves to be different (without any f.lux and other colors modifying stuff applied) it will probably mean that W10 somehow has more aggressive approach to dithering or it sends out different colors to the screen than W10 would do.
Anyway - it's a great find, that may prove really helpful, I only wonder if it's related to Windows or Dasung itself.
E: The thing with f.lux is really strange - it shouldn't be visible as a dithering animation since the screen would show the same color. It may mean that colors with f.lux are pulsating in a narrow range, but it doesn't make sense from software that should make the display better. Or maybe your f.lux uses fade-in animation to change colors after being turned on? It would require some time for it to finish fading and settle on a given color. Another option is that Dasung uses animated dithering to show shades that are between "static" dithering views, but still - it doesn't look reasonable.