Silverlight DomainDataSource in code-behind not loading all rows

Question

I have a domain data source in Silverlight 4. I'm setting it up in the code behind, and I'm also using a RadDataPager and RadGridView.

DomainDataSource dds = new DomainDataSource();

dds.QueryName = "MyQueryName";
dds.DomainContext = ctx;
dds.LoadSize = 10;
dds.PageSize = 10;
dds.AutoLoad = true;

radDataPager1.PageSize = 10;
radDataPager1.Source = dds.Data;
radGridView1.ItemsSource = dds.Data;

dds.Load();

The first time this loads, the dds.Data.Count is 8, and only 8 items show up in the grid view, even though the dds.Data.PageSize is 10. After I page to the next page, all 10 objects are loaded like they should be.

I'm new to Silverlight, and have no idea what is going on here. Am I loading the data wrong? Any ideas?