It's the same syndrome as this - Windows screwing up the UAC-shield-overlay process, and displaying a generic icon instead, as a fail-back. It's not restricted to Win7...
You might be able to re-set it by drilling into the shortcut's Properties and using Change Icon, and/or deleting and re-creating the shortcut.
You might be able to re-set it by drilling into the shortcut's Properties and using Change Icon, and/or deleting and re-creating the shortcut.