What I think should happen is that org.hibernate.osgi.OsgiSessionFactoryService and org.hibernate.osgi.OsgiPersistenceProviderService should each create the OsgiClassLoaderService per each call to their #getService calls.

+1. IIRC, that was always the intention, but it was ignored since we still had the static "TCCL override" concept in that ClassLoaderHelper. If all uses of that helper could be removed, instead solely relying on the ClassLoaderService, then this change should definitely happen.