IndexedEmbedded not updating other side of relationship?

Question

I have a one to many, let's say company-to-employees. I am trying to use [IndexEmbedded] on Employee's Company reference, so I can perform a employee query similar to: "Company.Name:IBM". When inserting the employee, this works fine. However, if I update the Company instance, the lucene index on the employee side does not get updated. The Lucene index does get updated if I update the employee in some other way in the same transaction.

I updated my NHibernate Search based on the advice from this question, but the index still does not get updated. Here's my relevant configuration:

c.SetListener(ListenerType.PostUpdate, new FullTextIndexEventListener());
c.SetListener(ListenerType.PostInsert, new FullTextIndexEventListener());
c.SetListener(ListenerType.PostDelete, new FullTextIndexEventListener());
c.SetListener(ListenerType.PostCollectionUpdate, new FullTextIndexCollectionEventListener());
c.SetListener(ListenerType.PostCollectionRecreate, new FullTextIndexCollectionEventListener());
c.SetListener(ListenerType.PostCollectionRemove, new FullTextIndexCollectionEventListener());

Any advice much appreciated.