Hi there,
Sorry for late response. The problem seems to be same bug with Rob's link. Rob, you attached a patch for that bug, and it seems that you are the assignee. if is there anything that I could help (provide the test scenerio or sth like that), I'd like to. Hope that you resolve it very soon :)
PS: For hacking, we put corresponding quartz.jar manually to JBoss's deployment path and change the immute bit so that it could never be deleted on clean/publish processes. If there is a need to open an issue on JBoss Tools, I will, but I think its unnecessary to open a new one for similar bug on WTP.
Thanks in advance.