In class

org.hibernate.collection.spi.AbstractPersistentCollection<E> implements Serializable PersistentCollection<E> the method prepareForPossibleLoadingOutsideTransaction is called from unsetSession like following from class {{ org.hibernate.engine.internal}}.StatefulPersistenceContext:

	final SharedSessionContractImplementor session = getSession();
		if ( collectionEntries != null ) {
			IdentityMap.onEachKey( collectionEntries, k -> k.unsetSession( session ) );
		}

If you see in the screenshot, the {{currentSession}}holds a session object but this.session is null, which causes {{allowLoadOutsideTransaction}}to be set as false and throws exception later in {{prepareForPossibleLoadingOutsideTransaction}}becuase both sessiion and tempsession are null.

I think currentsession variable should be passed to prepareForPossibleLoadingOutsideTransaction }}to check if a transaction is allowed outside transaction or not. {{allowLoadOutsideTransaction = session.getFactory().getSessionFactoryOptions().isInitializeLazyStateOutsideTransactionsEnabled();