Waiting: This icon appears when an app is in a queue to be download. This blank icon is often seen when you have downloaded multiple apps. In these cases, some apps will be actively downloading ...

If you have noticed an icon with 2 small blue overlays, then know that it has been placed there by the Windows OS to indicate that the file or folder has been compressed to save disk space.

Some users have experienced abnormal behavior where their Windows 11/10 Taskbar icons are not showing, become invisible, go missing, become empty or blank or disappear & reappear randomly.