Submenu doesn't show actions on Mac if added a second time

You add a sub menu 'ExportTo' with one or more actions to a main menu 'File' in the menubar. If you clear the menu File and add again the ExportTo menu, the ExportTo doesn't show any action more. This worked fine till 4.8.5 on under windows with the newer qt versions, but with the 5.2.0 and 5.1.0 under Max OS X 10.9 it doesn't work any longer.

Attachend you find a sample application. If you start the application, the first time you open the menu File you see the actions in the ExportTo menu, the second time you open the menu File the ExportTo menu is empty.