Win11 System tray Safely Remove Hardware icon disappears while a USB drive is still connected

Even if the USB flash drive is still connected to the computer, the Safely Remove Hardware and Eject Media icon in the system tray will disappear. Although the drive is still accessible in File Explorer, you cannot safely eject it.

After unplugging and reinserting the drive, the icon will temporarily reappear, but it may disappear again after a short while.