EDIT

I seem to remember that I did the following:

1. RegistrationWorkingsetEditor at http://api.phycobank.org/phycobank/app/registration#!workingset/1e1ea80f-4929-4d83-ab35-ae0391e1275b while working on #8155
2. open type designation editor for http://phycobankl.org/100992
3. close
4. open blocking registrations
5. wait ....
6. open type designation editor for http://phycobankl.org/100992

i did not try to reproduce this

[phycobank] 2019-02-28 16:20:48,846 WARN [net.sf.ehcache.config.CacheConfiguration] - Cache: eu.etaxonomy.cdm.vaadin.view.name.SpecimenTypeDesignationWorkingsetEditorPresenter1443081017 has a maxElementsInMemory of 0. This might lead to performance degradation or OutOfMemoryError at Terracotta client.From Ehcache 2.0 onwards this has been changed to mean a store with no capacity limit. Set it to 1 if you want no elements cached in memory
[phycobank] 2019-02-28 16:20:48,883 INFO [eu.etaxonomy.cdm.cache.CdmTransientEntityCacher] - Cdm Entity with id : 790 already exists in permanent cache. Ignoring put.
[phycobank] 2019-02-28 16:20:48,883 INFO [eu.etaxonomy.cdm.cache.CdmTransientEntityCacher] - Cdm Entity with id : 273 already exists in permanent cache. Ignoring put.
[phycobank] 2019-02-28 16:20:48,883 INFO [eu.etaxonomy.cdm.cache.CdmTransientEntityCacher] - Cdm Entity with id : 853 already exists in permanent cache. Ignoring put.
[phycobank] 2019-02-28 16:20:48,917 ERROR [com.flowingcode.vaadin.addons.errorwindow.ErrorWindow] - Error occurred 8ecb2797-9d64-45ce-bc8e-b812653fc0ce
com.vaadin.event.ListenerMethod$MethodException: Invocation of method buttonClick in eu.etaxonomy.cdm.vaadin.view.registration.RegistrationWorksetViewBean$$Lambda$193/1653176108 failed.
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:533)
        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:200)
        at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:163)
        at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1015)
        at com.vaadin.ui.Button.fireClick(Button.java:377)
        at com.vaadin.ui.Button$1.click(Button.java:54)
        at sun.reflect.GeneratedMethodAccessor716.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:158)
        at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:119)
        at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:437)
        at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:402)
        at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:273)
        at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90)
        at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
        at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1435)
        at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:380)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:808)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:122)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:169)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:158)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.oauth2.provider.authentication.OAuth2AuthenticationProcessingFilter.doFilter(OAuth2AuthenticationProcessingFilter.java:176)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
        at org.eclipse.jetty.server.Server.handle(Server.java:497)
        at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
        at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
        at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
        at java.lang.Thread.run(Thread.java:748)
Caused by: com.vaadin.data.Buffered$SourceException
        at com.vaadin.ui.AbstractField.setPropertyDataSource(AbstractField.java:664)
        at com.vaadin.data.fieldgroup.FieldGroup.bind(FieldGroup.java:273)
        at com.vaadin.data.fieldgroup.BeanFieldGroup.bind(BeanFieldGroup.java:155)
        at com.vaadin.data.fieldgroup.FieldGroup.bindFields(FieldGroup.java:113)
        at com.vaadin.data.fieldgroup.FieldGroup.setItemDataSource(FieldGroup.java:103)
        at com.vaadin.data.fieldgroup.BeanFieldGroup.setItemDataSource(BeanFieldGroup.java:126)
        at com.vaadin.data.fieldgroup.BeanFieldGroup.setItemDataSource(BeanFieldGroup.java:119)
        at eu.etaxonomy.vaadin.mvp.AbstractPopupEditor.loadInEditor(AbstractPopupEditor.java:811)
        at eu.etaxonomy.cdm.vaadin.view.registration.RegistrationWorkingsetPresenter.onTypeDesignationWorkingsetAdd(RegistrationWorkingsetPresenter.java:627)
        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.vaadin.spring.events.internal.MethodListenerWrapper.publish(MethodListenerWrapper.java:78)
        at org.vaadin.spring.events.internal.ListenerCollection.publish(ListenerCollection.java:167)
        at org.vaadin.spring.events.internal.ScopedEventBus.publish(ScopedEventBus.java:116)
        at org.vaadin.spring.events.internal.ScopedEventBus.publish(ScopedEventBus.java:109)
        at eu.etaxonomy.cdm.vaadin.view.registration.RegistrationWorksetViewBean.addNewTypeDesignationWorkingset(RegistrationWorksetViewBean.java:503)
        at eu.etaxonomy.cdm.vaadin.view.registration.RegistrationWorksetViewBean.lambda$chooseNewTypeRegistrationWorkingset$ac0bb240$1(RegistrationWorksetViewBean.java:483)
        at sun.reflect.GeneratedMethodAccessor681.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
        ... 75 more
Caused by: org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: eu.etaxonomy.cdm.model.common.DefinedTermBase.representations
        at org.hibernate.engine.internal.Collections.processDereferencedCollection(Collections.java:99)
        at org.hibernate.engine.internal.Collections.processUnreachableCollection(Collections.java:50)
        at org.hibernate.event.internal.AbstractFlushingEventListener.flushCollections(AbstractFlushingEventListener.java:243)
        at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:86)
        at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:44)
        at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
        at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1767)
        at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:363)
        at eu.etaxonomy.cdm.persistence.dao.hibernate.common.CdmEntityDaoBase.findByUuid(CdmEntityDaoBase.java:423)
        at eu.etaxonomy.cdm.persistence.dao.hibernate.common.CdmEntityDaoBase.load(CdmEntityDaoBase.java:771)
        at eu.etaxonomy.cdm.persistence.dao.hibernate.common.VersionableDaoBase.load(VersionableDaoBase.java:113)
        at eu.etaxonomy.cdm.persistence.dao.hibernate.common.VersionableDaoBase.load(VersionableDaoBase.java:106)
        at eu.etaxonomy.cdm.persistence.dao.hibernate.common.VersionableDaoBase.load(VersionableDaoBase.java:36)
        at eu.etaxonomy.cdm.api.service.ServiceBase.load(ServiceBase.java:214)
        at sun.reflect.GeneratedMethodAccessor746.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
        at com.sun.proxy.$Proxy170.load(Unknown Source)
        at eu.etaxonomy.cdm.vaadin.component.CdmBeanItemContainerFactory.buildTermItemContainer(CdmBeanItemContainerFactory.java:89)
        at eu.etaxonomy.cdm.vaadin.view.name.SpecimenTypeDesignationWorkingsetEditorPresenter$1.create(SpecimenTypeDesignationWorkingsetEditorPresenter.java:214)
        at eu.etaxonomy.cdm.vaadin.view.name.SpecimenTypeDesignationWorkingsetEditorPresenter$1.create(SpecimenTypeDesignationWorkingsetEditorPresenter.java:207)
        at org.vaadin.viritin.fields.AbstractElementCollection.createEditorInstance(AbstractElementCollection.java:282)
        at org.vaadin.viritin.fields.AbstractElementCollection.getFieldGroupFor(AbstractElementCollection.java:327)
        at org.vaadin.viritin.fields.ElementCollectionField.addInternalElement(ElementCollectionField.java:101)
        at org.vaadin.viritin.fields.ElementCollectionField.onElementAdded(ElementCollectionField.java:293)
        at org.vaadin.viritin.fields.AbstractElementCollection.setInternalValue(AbstractElementCollection.java:444)
        at org.vaadin.viritin.fields.AbstractElementCollection.setInternalValue(AbstractElementCollection.java:45)
        at com.vaadin.ui.AbstractField.setPropertyDataSource(AbstractField.java:657)
        ... 97 more