This issue is particularly noticeable in Electron-based apps (such as VS Code, Termius and so on), where an abnormal white line appears at the very top of the window when macOS is in Light Mode. Interestingly, it behaves normal when macOS switches to Dark Mode (I have attached screenshot examples). It would be more apparent with a dark background and app is in dark theme. This bug seems to persist across multiple macOS versions. For additional context, this widespread behavior has also been documented in a VS Code GitHub issue: https://github.com/microsoft/vscode/issues/144389. Since this flaw impacts a wide range of applications, it is highly likely a systemic issue that needs to be addressed by the macOS team, rather than individual app developers. This visual glitch is quite distracting during daily use, I have submitted this issue to Apple team. I hope more people could feedback this to Apple to fix it.