WICKET-5164 Wicket made org.apache.wicket.page.PageStoreManager.SessionEntry a javax.servlet.http.HttpSessionBindingListener to be notified when this session attribute is removed to be able to clean the disk data store when the session is replaced.
This causes problems on Glassfish server (ver. 3 and 4) because GF notifies the HttpSessionBindingListener no matter whether the new value is different from the old one.
Jetty and Tomcat check the new against the old value by identity and there is no problem.
See this mail discussion for more details: