When installing or uninstalling with a package manager on Mint the icon cache is updated. From the CLI you get the error message:

gtk-update-icon-cache /usr/share/icons/hicolor gtk-update-icon-cache: The generated cache was invalid.

Researching the most common cause for this error is a space in the icon file name. A search in this folder shows there to be three such filenames:

/usr/share/icons/hicolor/128x128/apps/Rclone UI.png
/usr/share/icons/hicolor/256x256@2/apps/Rclone UI.png
/usr/share/icons/hicolor/32x32/apps/Rclone UI.png'

Changing these to Rclone-UI.png and then rebuilding the cache with:

sudo gtk-update-icon-cache /usr/share/icons/hicolor results in the output:

gtk-update-icon-cache: Cache file created successfully.

The icon file has to be updated for any desktop or menu .desktop files with Rclone-UI in the search box. (In Mint). I assume this will have the same effect in all debian and ubuntu gtk desktops. Suggested fix, on upgrade remove icon files with a space and replace with a filename with no space.