I have created a multi-tab application with fluentribbon, and added to a LayoutsPageBase in the next order:
RibbonController.Current.AddRibbonTabToPage(tab1, this, true);
RibbonController.Current.AddRibbonTabToPage(tab2, this, false);
RibbonController.Current.AddRibbonTabToPage(tab3, this, false);

where tab1.Title="M3-HRMS-1", tab2.Title="M3-HRMS-2" and tab3.Title="M3-HRMS-3"

All tabs are displayed but sorted in the next order tab3->tab1->tab2, as displayed in the video, and after I made click in the tab3 the tabs are shifted and display in the right orders.