See http://opensource.atlassian.com/projects/hibernate/browse/HHH-2532 for the underlying issue. Hibernate 3.2.3 includes a temporary fix for the problem, but it doesn't work when org.jboss.ejb3.entity.TreeCacheProviderHook or OptimisticTreeCacheProviderHook are used as as the CacheProvider. For AS 4.2 need to ensure the problem is fixed when these classes are used.