Hold on, I actually think that whole thing is confirmation bias. Your brain seeing the flipped version as "better" just means you finally looked at it fresh, not that the light was wrong. Shadows from the bottom right are totally a thing, especially if your monitor brightness or the time of day made you lean that way, and honestly most regular people never even notice light direction unless they're looking for it. You probably just got bored of the old style and needed an excuse to change it up.

You still LAN partying with that OptiPlex, or is it just decoration now?

Six minutes is hardly a crisis. Figure it out and move on.