Websocket Error when using IE8 or IE9

[confile]

I use atmosphere 2.0RC3 with transport websockts and fallback streaming.
Everything works fine with modern browsers, but when I access my app with IE8 or IE9 I get the following errors in my server log.

Is there a way to catch these errors on the server? The strange thing is that the app works fine even in IE8 and IE9, despite the errors occur. What is wrong here?

2013-08-08 00:56:19,631 [http-nio-8080-exec-9] ERROR cpr.AtmosphereFramework  - AtmosphereFramework exception
java.lang.IllegalStateException: Not supported.
    at org.atmosphere.cpr.AtmosphereRequest.startAsync(AtmosphereRequest.java:594)
    at org.atmosphere.container.Servlet30CometSupport.suspend(Servlet30CometSupport.java:130)
    at org.atmosphere.container.Servlet30CometSupport.service(Servlet30CometSupport.java:105)
    at org.atmosphere.container.Tomcat7Servlet30SupportWithWebSocket.doService(Tomcat7Servlet30SupportWithWebSocket.java:65)
    at org.atmosphere.container.TomcatWebSocketUtil.doService(TomcatWebSocketUtil.java:87)
    at org.atmosphere.container.Tomcat7Servlet30SupportWithWebSocket.service(Tomcat7Servlet30SupportWithWebSocket.java:61)
    at org.atmosphere.cpr.AtmosphereFramework.doCometSupport(AtmosphereFramework.java:1594)
    at org.atmosphere.cpr.AtmosphereServlet.doPost(AtmosphereServlet.java:176)
    at org.atmosphere.cpr.AtmosphereServlet.doGet(AtmosphereServlet.java:162)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
2013-08-08 00:56:19,670 [http-nio-8080-exec-2] ERROR cpr.AtmosphereFramework  - AtmosphereFramework exception
java.lang.IllegalStateException: Not supported.
    at org.atmosphere.cpr.AtmosphereRequest.startAsync(AtmosphereRequest.java:594)
    at org.atmosphere.container.Servlet30CometSupport.suspend(Servlet30CometSupport.java:130)
    at org.atmosphere.container.Servlet30CometSupport.service(Servlet30CometSupport.java:105)
    at org.atmosphere.container.Tomcat7Servlet30SupportWithWebSocket.doService(Tomcat7Servlet30SupportWithWebSocket.java:65)
    at org.atmosphere.container.TomcatWebSocketUtil.doService(TomcatWebSocketUtil.java:87)
    at org.atmosphere.container.Tomcat7Servlet30SupportWithWebSocket.service(Tomcat7Servlet30SupportWithWebSocket.java:61)
    at org.atmosphere.cpr.AtmosphereFramework.doCometSupport(AtmosphereFramework.java:1594)
    at org.atmosphere.cpr.AtmosphereServlet.doPost(AtmosphereServlet.java:176)
    at org.atmosphere.cpr.AtmosphereServlet.doGet(AtmosphereServlet.java:162)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

my web.xml

<async-supported>true</async-supported>
<init-param>
   <param-name>org.atmosphere.useNative</param-name>
   <param-value>true</param-value>
</init-param>   

<init-param>
<param-name>org.atmosphere.cpr.AtmosphereInterceptor</param-name>
    <param-value>org.atmosphere.interceptor.HeartbeatInterceptor,org.atmosphere.interceptor.AtmosphereResourceLifecycleInterceptor,org.atmosphere.client.TrackMessageSizeInterceptor</param-value>
</init-param>

<init-param>
   <param-name>org.atmosphere.cpr.broadcaster.shareableThreadPool</param-name>
   <param-value>true</param-value>
</init-param>

<init-param>
   <param-name>org.atmosphere.cpr.sessionSupport</param-name>
   <param-value>true</param-value>
</init-param>
<init-param>
   <param-name>org.atmosphere.cpr.broadcasterCacheClass</param-name>
   <param-value>org.atmosphere.cache.UUIDBroadcasterCache</param-value>
</init-param>

[jfarcand]

Duplicate of #1218