title: NHibernate ThenFetchMany is retrieving duplicate children
body: <p>I have a parent object with a child collection containing one element, the child collection contains a "grandchild" collection containing 3 elements.</p>
  
  <p>I am loading the parent object from the database using NHibernate as follows</p>
  
  <pre><code>Parent parentObject = session.Query&lt;Parent&gt;()
      .FetchMany(x =&gt; x.Children)
      .ThenFetchMany(x =&gt; x.GrandChildren)
      .Where(x =&gt; x.Id = "someparentid")
      .Single();
  </code></pre>
  
  <p>What I'm finding is that there are duplicate children objects (3 in total) attached to the parent object when there should be only one. (There are 3 grandchild objects correctly attached to each child.) Eager loading the children collection only works correctly.</p>
  
  <p>Do you know how I can achieve loading of the full parent object without duplicate children?</p>