I've reproduced this as well with synchronousUpdate "true" (it just reduces the occurrence). I can assure you that it's not yet fixed in ICEfaces 1.5.2 as I'm working on the bug at this very moment ... (Note that ICEfaces 1.5.2 will ship once the outstanding bugs of current support customers are resolved, so a fix for this bug may or may not make the cut depending on timing.) The bug appears to be due to a race condition involving org.jboss.seam.core.Manager caused by potential concurrent handling of ICEfaces partialSubmit requests (ordering is not guaranteed, but concurrent handling would be unintended) . I am investigating this in detail now. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4000525#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...