I also confirm this. Steps to reproduce:
1) Open exactly two windows and minimize them to unity launcher. 2) Restore any one window and close it. 3) Result: The other window on Unity launcher cannot be restored to desktop by clicking on its icon on launcher.
I also confirm this. Steps to reproduce:
1) Open exactly two windows and minimize them to unity launcher.
2) Restore any one window and close it.
3) Result: The other window on Unity launcher cannot be restored to desktop by clicking on its icon on launcher.