Error if the payment method is updated

16:27:39,273 ERROR ExceptionMapperStandardImpl:39 - HHH000346: Error during managed flush [org.hibernate.PropertyValueException: not-null property references a null or transient value : org.olat.resource.accesscontrol.provider.paypal.model.PaypalAccessMethod.lastModified]
16:27:39,276  WARN DBImpl:203 - Caught Exception in DBImpl.commit. ^%^ >>>stack of 1.cause::javax.persistence.RollbackException: Error while committing the transaction
-> at org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:75)
   at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:71)
   at org.olat.core.commons.persistence.DBImpl.commit(DBImpl.java:712)
   at org.olat.core.commons.persistence.DBImpl.commitAndCloseSession(DBImpl.java:670)
   at org.olat.resource.accesscontrol.manager.ACMethodDAO.event(ACMethodDAO.java:98)
   at org.olat.core.util.event.AbstractEventBus$2.run(AbstractEventBus.java:171)
   at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
   at org.olat.core.util.event.AbstractEventBus.doFire(AbstractEventBus.java:168)
   at org.olat.core.util.event.AbstractEventBus.doFire(AbstractEventBus.java:141)
   at org.olat.commons.coordinate.cluster.jms.ClusterEventBus.serveMessage(ClusterEventBus.java:336)
   at org.olat.commons.coordinate.cluster.jms.ClusterEventBus.onMessage(ClusterEventBus.java:264)
>>>stack of 2.cause::javax.persistence.PersistenceException: org.hibernate.PropertyValueException: not-null property references a null or transient value : org.olat.resource.accesscontrol.provider.paypal.model.PaypalAccessMethod.lastModified
-> at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:147)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
   at org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:56)
   at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:71)
   at org.olat.core.commons.persistence.DBImpl.commit(DBImpl.java:712)
   at org.olat.core.commons.persistence.DBImpl.commitAndCloseSession(DBImpl.java:670)
   at org.olat.resource.accesscontrol.manager.ACMethodDAO.event(ACMethodDAO.java:98)
   at org.olat.core.util.event.AbstractEventBus$2.run(AbstractEventBus.java:171)
   at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
   at org.olat.core.util.event.AbstractEventBus.doFire(AbstractEventBus.java:168)
   at org.olat.core.util.event.AbstractEventBus.doFire(AbstractEventBus.java:141)
>>>stack of 3.cause::org.hibernate.PropertyValueException: not-null property references a null or transient value : org.olat.resource.accesscontrol.provider.paypal.model.PaypalAccessMethod.lastModified
-> at org.hibernate.engine.internal.Nullability.checkNullability(Nullability.java:92)
   at org.hibernate.event.internal.DefaultFlushEntityEventListener.scheduleUpdate(DefaultFlushEntityEventListener.java:288)
   at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:143)
   at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
   at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
   at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38)
   at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1428)
   at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:484)
   at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3190)
   at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2404)
   at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:467)