My guess is that you are seeing a manifestation of http://opensource.atlassian.com/projects/hibernate/browse/HHH-1796 There is absolutely no way that Hibernate would apply a DataVersion to a *query cache* region, as they logically should have no versioning info at all. Thus we use null DataVersion, which my testing (within the Hibernate test suite) shows is perfectly valid. writeLoad() pushing a null into the DataVersionAdapter.previousVersion should be fine... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3956994#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...