From making some errors in this error message, I noticed that this happens when you run insert / update in non-transactional mode. The explanation is given here .
This is because the table in which you are trying to update is not, and your update is performed inside a transaction.
As a rule, you should always commit (and roll back if an exception occurs) your transactions. Usually I never set auto commit to true, but in this case I would like to understand if this is really necessary, as indicated in the link above. Can you set the auto-commit to true on your connection to see if this has disappeared?
<property name="hibernate.connection.autocommit" value="true"/>
This link also contains several guides for managing sleep transactions.