I verified that SessionFactoryServiceContributor doesn't help WF either,
as we see the same problem.
I did hack together a unit test under ORM (using the WF integration
testing) that shows that we don't see the same problem when the
https://github.com/hibernate/hibernate-orm/tree/master/hibernate-jipijapa
integration classes are used.
It seems likely that something is wrong with the
https://github.com/wildfly/wildfly/tree/master/jpa/hibernate5_3/src/main/...
classes, that causes the problem that I am seeing.
Scott