I've a asynch handling testcase [1] in jbossws-cxf testsuite which is currently failing due to an exception on server side when trying to create the response asynchronously on a new thread:

17:42:42,855 INFO [stdout] (Thread-73) Responding on background thread...
17:42:42,858 ERROR [io.undertow.request] (default task-5) Blocking request failed io.undertow.server.HttpServerExchange@2bdab757: java.lang.IllegalArgumentException: UT010024: Response org.jboss.wsf.stack.cxf.HttpServletResponseExt@7c686d38 was not original or a wrapper
at io.undertow.servlet.spec.HttpServletResponseImpl.getResponseImpl(HttpServletResponseImpl.java:507) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchToPath(ServletInitialHandler.java:91) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.servlet.spec.AsyncContextImpl$2$1.handleRequest(AsyncContextImpl.java:149) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.server.HttpHandlers.executeRootHandler(HttpHandlers.java:53) [undertow-core-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.servlet.spec.AsyncContextImpl$2.run(AsyncContextImpl.java:146) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.servlet.spec.AsyncContextImpl$5.run(AsyncContextImpl.java:340) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at io.undertow.servlet.spec.AsyncContextImpl$TaskDispatchRunnable.run(AsyncContextImpl.java:406) [undertow-servlet-1.0.0.Alpha6.jar:1.0.0.Alpha6]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_13]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_13]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_13]

[1] http://anonsvn.jboss.org/repos/jbossws/stack/cxf/trunk/modules/testsuite/cxf-tests/src/test/java/org/jboss/test/ws/jaxws/samples/asynch/EndpointImpl.java