Please refer to the attached sample project. When the expander is in the columns that contains long text that has be resize the rows, the AutoSizeRows functionality doesn't work properly:

Workaround: set the MasterTemplate.SelfReferenceExpanderColumn property to a column that contains very short content:  

Me.RadGridView1.MasterTemplate.SelfReferenceExpanderColumn = Me.RadGridView1.Columns(1)