I recently upgraded from 1.3.0 to 1.4.0 and starting encountering an issue where the default (first) tab contents are not displayed upon load. Once you start clicking in the tab headings all is fine. However, the initial load shows an empty tab.
Punk is here: http://plnkr.co/edit/wtTLfsaEppmlyDOAad0L
The same occurs when using the default template as well. This did not occur in 1.3.0.