Alex, Do you understand how your fix of yesterday (see http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4049235#...) is not working? I see two possibilities, but I don't know the code that well, so both could be wrong... you might want to instrument for these... 1.) Imagine that acquireJobs() has just finished executing on one thread, and the engine is now working on those jobs. Another job for the same process instance is queued, and another thread picks it up. In my admittedly brief reading, I don't see what synchronizes access to the process instance. 2.) In your case, I believe the jobs will be on the subprocesses, but both threads end up modifying the parent process. Is there anything synchronizing access to the parent process? I don't see it. The key point appears to be ProcessInstance.end(). You should probably update the JIRA. Also, in the JIRA you might more pointedly refer to the forum discussion(s). -Ed Staub View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4049698#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...