This is really trivial, the problem is just a spurious log.info().
In RenderingFilter there is a catch for IOExceptions while streaming back resources. The exception is swallowed since it's typically a ClientAbortException (can happen). But after the catch there is no "return" and the flow continues just like the resource was not found.
The filter tries to forward to the 404 page, than it catches another exception due to the closed stream and log another info.