LDAP sync: concurrent update of user

2017-09-06 09:07:07,458 [mpTaskSpringExecutor-1] ERROR LDAPLoginManagerImpl  - OLAT::ERROR ^%^ N58-E695 ^%^ org.olat.ldap.manager ^%^ n/a ^%^ n/a ^%^ n/a ^%^ n/a ^%^ Error in LDAP batch sync, unknown reason
>>>stack of 1.cause::javax.persistence.OptimisticLockException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [org.olat.user.UserImpl#45849952]
-> at org.hibernate.internal.ExceptionConverterImpl.wrapStaleStateException(ExceptionConverterImpl.java:197)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:86)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
   at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:893)
   at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:867)
   at org.olat.user.UserManagerImpl.updateUser(UserManagerImpl.java:353)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.syncUser(LDAPLoginManagerImpl.java:483)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.doBatchSyncNewAndModifiedUsers(LDAPLoginManagerImpl.java:1188)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.doBatchSync(LDAPLoginManagerImpl.java:924)
   at org.olat.ldap.manager.LDAPLoginManagerImpl$1.run(LDAPLoginManagerImpl.java:195)
>>>stack of 2.cause::org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) : [org.olat.user.UserImpl#45849952]
-> at org.hibernate.event.internal.DefaultMergeEventListener.entityIsDetached(DefaultMergeEventListener.java:322)
   at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:170)
   at org.hibernate.event.internal.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:69)
   at org.hibernate.internal.SessionImpl.fireMerge(SessionImpl.java:881)
   at org.hibernate.internal.SessionImpl.merge(SessionImpl.java:867)
   at org.olat.user.UserManagerImpl.updateUser(UserManagerImpl.java:353)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.syncUser(LDAPLoginManagerImpl.java:483)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.doBatchSyncNewAndModifiedUsers(LDAPLoginManagerImpl.java:1188)
   at org.olat.ldap.manager.LDAPLoginManagerImpl.doBatchSync(LDAPLoginManagerImpl.java:924)
   at org.olat.ldap.manager.LDAPLoginManagerImpl$1.run(LDAPLoginManagerImpl.java:195)
   at org.olat.core.commons.services.taskexecutor.model.DBSecureRunnable.run(DBSecureRunnable.java:42)