Critical Description
FacesContextFactoryImpl class that implements the JSF FacesContextFactory interface is not respecting the specification of the getFacesContext method.
Indeed JSF spec says the signature of the method is the following:
getFacesContext(java.lang.Object context, java.lang.Object request, java.lang.Object response, javax.faces.lifecycle.Lifecycle lifecycle)
So you would expect to pass as the first object the PortletContext object (and that's actually what the reference implementation JSF bridge is expecting).
However FacesContextFactoryImpl version is taking as the first parameter a PortletConfig instead of a PortletContext.
This cause third party software to crash.