'A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance' exception in Hibernate

Issue

• A OneToMany collection (e.g. Employee.tasks) marked with orphanRemoval = true is set to null and the exception below is raised when the owning entity (e.g. Employee) is flushed

  ... org.hibernate.HibernateException: A collection with cascade="all-delete-orphan" was no longer referenced by the owning entity instance: support.hibernate.entity.Employee.tasks
          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.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38)
          at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1295)
          at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:468)
          at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3159)
          ...