org.hibernate.jpa.spi.HibernateEntityManagerImplementor#convert() is invoked through {{ o.h.jpa.internal.TransactionImpl}}. This is ORM's impl. at the moment, so we have no way of ammending this conversion logic. Probably it needs some change on the ORM side to be able to do so (HibernateEntityManagerImplementor passes a reference to this)).

I don't think it's a huge problem, it only causes OGM's EntityAlreadyExistsException to be mapped into the generic JPA PersistenceException instead of the more specific EntityExistsException.