Major Description
If the resource target for the above is a Face view, the bridge runs through/executesd the normal Faces lifecycle to render the resource. It dispatches to the view JSP using forward. In the regular case (nonResource) this is actually translated by Pluto into a servlet include simulating the forward. However for a resource its an actual servlet forward. Tomcat closes the response and flushes the markup (from it) at the end of the forward. So unless the response is wrapped/buffered Faces can't write after the forward.
So the solution is to be sure the response is always wrapped/buffered (similar to the base Faces implementation). Do this for all requests (render and resource) as we don't know how the portlet container we are running on may be working