JPA: Attempted to deploy PersistenceUnit while being in the wrong state

For a while I would see the following exception at random times in logs while using JPA in Spring.:

org.springframework.transaction.CannotCreateTransactionException:
Could not open JPA EntityManager for transaction;
nested exception is javax.persistence.PersistenceException:
Exception [TOPLINK-28013] (Oracle TopLink Essentials - 2.1 (Build 60 (11/17/2008))):
oracle.toplink.essentials.exceptions.EntityManagerSetupException
Exception Description: Attempted to deploy PersistenceUnit [harborPU]
while being in the wrong state [Undeployed].
Close all factories for this PersistenceUnit.

Turns out the
PersistenceUnit would be left in the wrong state if the EntityManagerFactory in the JpaTemplate has not been closed. I assumed Spring would take care of this for me, but the behaviour wasn't consistent. In my DAO, I tried adding an explicit call to getJpaTemplate().getEntityManagerFactory().close(). Of course that didn't work because the method where I put the call was within the transaction, leading to:

org.springframework.dao.InvalidDataAccessApiUsageException: 
Attempting to execute an operation on a closed EntityManager.; 
nested exception is java.lang.IllegalStateException: 
Attempting to execute an operation on a closed EntityManager.

Therefore, I had to call the method from within the class using the DAO that made the call to the method involved in the transaction.

I wonder if this has something to do with my transaction setup:

<bean id="entityManagerFactory" 
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="jpaVendorAdapter">
      <bean class="org.springframework.orm.jpa.vendor.TopLinkJpaVendorAdapter">
        <property name="database"    value="MYSQL"/>
        <property name="showSql"     value="true" />
        <!-- set to true if you want the vendor to create the database for you on startup -->
        <property name="generateDdl" value="false" />
      </bean>
    </property>
    <property name="loadTimeWeaver">
      <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/>
    </property>
  </bean>
  
  <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
    <property name="dataSource" ref="dataSource"/>
  </bean>

    <tx:advice id="txAdvice">
    <tx:attributes>
      <tx:method name="get*"    propagation="REQUIRED"/>
    </tx:attributes>
  </tx:advice>
  
  <aop:config>
    <!-- interface to my DAO
    <aop:advisor pointcut="execution(* *..MyDaoService.*(..))" advice-ref="txAdvice"/>    
  </aop:config>

If you have any insight, please leave a comment :).