To reproduce use the attached project.
Workaround:
Private Sub gvData_UserAddedRow(sender As Object, e As Telerik.WinControls.UI.GridViewRowEventArgs) Handles gvData.UserAddedRow
Dim pi = GetType(GridViewNewRowInfo).GetProperty("MoveToLastRow", Reflection.BindingFlags.Instance Or Reflection.BindingFlags.NonPublic)
pi.SetValue(Me.gvData.MasterView.TableAddNewRow, True, Nothing)
End Sub