a4j:support on WebSphere

[nata]

Hello!
I have a problem with a4j:support component on WebSphere AS.

Code like this works fine in tomcat, but in WebSphere it works strange. When validation is failed after a4j:commandButton submit and then it is passed after
a4j:support submit then button action executes with new valid submitted value instead of only validation check.

<a4j:form>
...
<h:inputText
 validator="#{handler['validateQuantity']}"
 required="true">

 <a4j:support event="onchange"
 eventsQueue="selectProductQueue"
 requestDelay="500"
 reRender="some component ids" />
</h:inputText>
...
<a4j:commandButton type="submit"
 eventsQueue="selectProductQueue"
 requestDelay="500"
 action="#{handler['addOrder']}"
 reRender="some ids" />
</a4j:form>

Thanks.