I've noticed that a some shortcut icons on my desktop will randomly change to other icons on my desktop.
Example: I have a shortcut to Cygwin, Git, Computer, Documents, Chrome, etc. The Cygwin shortcut will start off as the correct icon, however, after some restarts the Cygwin icon will change to the Chrome icon, then the Computer icon, then the Git Bash icon. It's completely random and never stops changing. Once the icon changes from the original, it never goes back to it's original state.
I'm using Windows 7 RTM Enterprise and I can remember this happening since Windows XP.