GOKb harvest job ends in failure

On harvesting from GOKb the job ends with "Failure" status.
The rkb_sync_status in diku_mod_agreements.remotekb is left as 'in-process' leading all subsequent harvest jobs to do nothing but report "Success".

In debug log there is the following error:

2019-11-13 18:01:04.895 DEBUG — [pool-4-thread-1] org.olf.kb.adapters.GOKbOAIAdapter : GOKbOAIAdapter::freshen - exiting URI: http://gokbt.gbv.de/gokb/oai/index/packages
2019-11-13 18:01:04.912 ERROR — [pool-4-thread-1] org.olf.general.jobs.JobRunnerService : Job execution failed

org.springframework.dao.InvalidDataAccessApiUsageException: attempted to lock a deleted instance: org.olf.kb.RemoteKB#25ad48a0-7393-49d3-9b36-02d98161b11a; nested exception is org.hibernate.ObjectDeletedException: attempted to lock a deleted instance: org.olf.kb.RemoteKB#25ad48a0-7393-49d3-9b36-02d98161b11a
at org.springframework.orm.hibernate5.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:271)
at org.grails.orm.hibernate.GrailsHibernateTemplate.convertHibernateAccessException(GrailsHibernateTemplate.java:724)
at org.grails.orm.hibernate.GrailsHibernateTemplate.doExecute(GrailsHibernateTemplate.java:303)
at org.grails.orm.hibernate.GrailsHibernateTemplate.lock(GrailsHibernateTemplate.java:444)
at org.grails.orm.hibernate.AbstractHibernateGormInstanceApi.lock(AbstractHibernateGormInstanceApi.groovy:234)
at org.grails.datastore.gorm.GormEntity$Trait$Helper.lock(GormEntity.groovy:72)
at org.grails.datastore.gorm.GormEntity$Trait$Helper$lock$7.call(Unknown Source)
at org.olf.kb.RemoteKB.lock(RemoteKB.groovy)
at org.olf.kb.RemoteKB.lock(RemoteKB.groovy)
at org.grails.datastore.gorm.GormEntity$lock$0.call(Unknown Source)
at org.olf.KbHarvestService$_triggerCacheUpdate_closure3$_closure5.doCall(KbHarvestService.groovy:130)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:264)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:420)
at groovy.lang.Closure.call(Closure.java:436)
at grails.gorm.transactions.GrailsTransactionTemplate$2.doInTransaction(GrailsTransactionTemplate.groovy:94)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
at grails.gorm.transactions.GrailsTransactionTemplate.execute(GrailsTransactionTemplate.groovy:91)
at org.grails.datastore.gorm.GormStaticApi.withTransaction(GormStaticApi.groovy:1014)
at org.grails.datastore.gorm.GormStaticApi.withTransaction(GormStaticApi.groovy:966)
at org.grails.datastore.gorm.GormStaticApi.withNewTransaction(GormStaticApi.groovy:927)
at org.grails.datastore.gorm.GormEntity$Trait$Helper.withNewTransaction(GormEntity.groovy:952)
at org.grails.datastore.gorm.GormEntity$Trait$Helper$withNewTransaction$6.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
at org.grails.datastore.gorm.GormEntity$Trait$Helper$withNewTransaction$6.call(Unknown Source)
at org.olf.kb.RemoteKB.withNewTransaction(RemoteKB.groovy)
at org.olf.kb.RemoteKB$withNewTransaction$1.call(Unknown Source)
at org.olf.KbHarvestService$_triggerCacheUpdate_closure3.doCall(KbHarvestService.groovy:128)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:264)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:420)
at groovy.lang.Closure.call(Closure.java:436)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2125)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2110)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.each(DefaultGroovyMethods.java:2151)
at org.codehaus.groovy.runtime.dgm$163.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:274)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:56)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:128)
at org.olf.KbHarvestService.triggerCacheUpdate(KbHarvestService.groovy:93)
at org.olf.KbHarvestService$triggerCacheUpdate.call(Unknown Source)
at org.olf.general.jobs.PackageIngestJob$_closure1.doCall(PackageIngestJob.groovy:10)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:264)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1099)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:420)
at groovy.lang.Closure.call(Closure.java:414)
at java_util_concurrent_Callable$call.call(Unknown Source)
at org.olf.general.jobs.JobRunnerService$_enqueueJob_closure4$_closure7$_closure8.doCall(JobRunnerService.groovy:131)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:264)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:420)
at groovy.lang.Closure.call(Closure.java:436)
at grails.gorm.multitenancy.Tenants$_withId_closure2$_closure6.doCall(Tenants.groovy:265)
at grails.gorm.multitenancy.Tenants$_withId_closure2$_closure6.call(Tenants.groovy)
at org.grails.orm.hibernate.GrailsHibernateTemplate$1.doInHibernate(GrailsHibernateTemplate.java:153)
at org.grails.orm.hibernate.GrailsHibernateTemplate.doExecute(GrailsHibernateTemplate.java:299)
at org.grails.orm.hibernate.GrailsHibernateTemplate.execute(GrailsHibernateTemplate.java:243)
at org.grails.orm.hibernate.GrailsHibernateTemplate.executeWithNewSession(GrailsHibernateTemplate.java:150)
at org.grails.orm.hibernate.GrailsHibernateTemplate.executeWithExistingOrCreateNewSession(GrailsHibernateTemplate.java:209)
at org.grails.orm.hibernate.AbstractHibernateDatastore.withNewSession(AbstractHibernateDatastore.java:369)
at grails.gorm.multitenancy.Tenants$_withId_closure2.doCall(Tenants.groovy:258)
at grails.gorm.multitenancy.Tenants$_withId_closure2.call(Tenants.groovy)
at grails.gorm.multitenancy.Tenants$CurrentTenant.withTenant(Tenants.groovy:358)
at grails.gorm.multitenancy.Tenants.withId(Tenants.groovy:236)
at grails.gorm.multitenancy.Tenants.withId(Tenants.groovy:169)
at grails.gorm.multitenancy.Tenants$withId.call(Unknown Source)
at org.olf.general.jobs.JobRunnerService$_enqueueJob_closure4$_closure7.doCall(JobRunnerService.groovy:126)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:98)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:264)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1099)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1034)
at groovy.lang.Closure.call(Closure.java:420)
at groovy.lang.Closure.call(Closure.java:414)
at groovy.lang.Closure.run(Closure.java:501)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.hibernate.ObjectDeletedException: attempted to lock a deleted instance: org.olf.kb.RemoteKB#25ad48a0-7393-49d3-9b36-02d98161b11a
at org.hibernate.event.internal.AbstractLockUpgradeEventListener.upgradeLock(AbstractLockUpgradeEventListener.java:50)
at org.hibernate.event.internal.DefaultLockEventListener.onLock(DefaultLockEventListener.java:82)
at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:741)
at org.hibernate.internal.SessionImpl.fireLock(SessionImpl.java:734)
at org.hibernate.internal.SessionImpl.access$2300(SessionImpl.java:167)
at org.hibernate.internal.SessionImpl$LockRequestImpl.lock(SessionImpl.java:2644)
at org.grails.orm.hibernate.GrailsHibernateTemplate$10.doInHibernate(GrailsHibernateTemplate.java:446)
at org.grails.orm.hibernate.GrailsHibernateTemplate.doExecute(GrailsHibernateTemplate.java:299)
... 106 common frames omitted

2019-11-13 18:01:04.914 DEBUG — [pool-4-thread-1] org.olf.general.jobs.JobRunnerService : Finished task with jobId 481e0be8-8a20-4b44-a9ae-52b5a4b09d49 and tenantId diku_mod_agreements