Related Issue: https://hibernate.atlassian.net/browse/HHH-12585?jql=text%20~%20%22DefaultFlushEntityEventListener%22
Related Commit: https://github.com/hibernate/hibernate-orm/commit/9b00aaf9a55f9879a512b34c13dd25425264494b

skipping the interceptor if the entity is already dirty seem legit, but this way the interceptor will never be invoked, denying the opportunity to further modify the instance or simply intercept the update.