HibernateException "Unable to resolve owner of loading collection ..." in EAP 6

Issue

• An entity class uses an @Embeddable key class which consists of one or more String properties
• An instance of the key class instantiated using a String with one or more trailing spaces is used to load an entity from a Sybase database

DepartmentKey key = new DepartmentPK("engineering     ");
Department dep = entityManager.find(Department.class, key);

• When navigating a *toMany association from the returned entity, the following exception may be raised:

org.hibernate.HibernateException: Unable to resolve owner of loading collection [[org.test.Department.employees#component[name]{name=engineering}]] for second level caching
        at org.hibernate.engine.loading.internal.CollectionLoadContext.addCollectionToCache(CollectionLoadContext.java:321)
        at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollection(CollectionLoadContext.java:262)
        at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:233)
        at org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:209)
        at org.hibernate.loader.Loader.endCollectionLoad(Loader.java:1150)
        at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1119)
        at org.hibernate.loader.Loader.processResultSet(Loader.java:964)
        at org.hibernate.loader.Loader.doQuery(Loader.java:911)
        at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342)
        at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:312)
        at org.hibernate.loader.Loader.loadCollection(Loader.java:2238)
        at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:65)
        at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:674)
        at org.hibernate.event.internal.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:85)
        at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1855)
        at org.hibernate.collection.internal.AbstractPersistentCollection$4.doWork(AbstractPersistentCollection.java:549)
        at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:234)
        at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
        at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
        at org.hibernate.collection.internal.PersistentSet.iterator(PersistentSet.java:180)

• In cases where both the primary key object and foreign key object have been loaded into the level 2 cache in a different persistence context (session or entity manager) prior to the above operations, the association navigation may simply return an empty result set (without raising an exception) - a result which is still unexpected if there are foreign key rows in the database that match the persisted primary key