That’s a Windows 11 bug with File Explorer, not something wrong with your folders. Explorer sometimes fails to refresh the view, so it looks empty until you hit F5. It doesn’t happen on Windows 10 because the Explorer interface was redesigned in Windows 11 and still has some glitches.
Keeping Windows fully updated helps, since Microsoft has been rolling out fixes in cumulative updates. You can also reduce how often it happens by turning off Quick Access and disabling “Show files from Office.com” in Explorer Options. If you set Explorer to open to “This PC” instead of Quick Access, it usually behaves better.
There isn’t a permanent fix yet, so the best you can do is apply updates and these settings until Microsoft issues a full patch.