I was have same issue, but i found working workaround for it in this link : http://forum.primefaces.org/viewtopic.php?f=14&t=36652
Seems the issue is :
It seems primefaces ext js files are not loaded unless we use at least one ext tag.
Since i was not using one on the main page..but it was in a dynamic ui:include, it was loading only after a hard refresh of main page.
So you can add dummy pe tag in your main template just after <h:body>
like this :
<pe:blockUI></pe:blockUI>
Or like :
<pe:inputNumber style="display:none" />
Its worked for me actually.