Please see FlatDataExample.xaml.cs in the attached project.

Note this section:

     // Crashes here if hierarchies and levels have the same name.
            // However, changing names causes hierarchies not to display in pivot grid.

            PeopleGrid.DataSource.Filters.Add(PeopleGrid.DataSource.CreateFilterViewModel(
                PeopleGrid.DataSource.Cube.Dimensions["Gender"].Hierarchies.First()));

            PeopleGrid.DataSource.Filters.Add(PeopleGrid.DataSource.CreateFilterViewModel(
                PeopleGrid.DataSource.Cube.Dimensions["TypeCode"].Hierarchies.First()));
    
I've tried changing the hierarchy and level names however when I do that the pivot grid does not display any dimenions.
The code below is a WORKING page from a different project that is running the same version of Infragistics (I checked each dll).
Why does it work?

 <igFlatData:FlatDataSource x:Key="RollBookDataSource" x:Shared="False"
                                   Rows="[PIMCO_DESC].[Product],[BROKER].[Broker]"
                                   Columns="[Measure].[Measure]"
                                   Measures="Long,Short,Net">
            <igFlatData:FlatDataSource.ConnectionSettings>
                <igFlatData:FlatDataConnectionSettings ItemsSource="{Binding}"/>
            </igFlatData:FlatDataSource.ConnectionSettings>
            <igFlatData:FlatDataSource.CubesSettings>
                <igFlatData:CubeMetadata DataTypeFullName="Poolman.Models.TBARollPivotItem">
                    <igFlatData:DimensionMetadata SourcePropertyName="Long"
                                                  DisplayFormat="{}{0:#,#;(#,#)}"/>
                    <igFlatData:DimensionMetadata SourcePropertyName="Short"
                                                  DisplayFormat="{}{0:#,#;(#,#)}"/>
                    <igFlatData:DimensionMetadata SourcePropertyName="Net"
                                                  DisplayFormat="{}{0:#,#;(#,#)}"/>
                </igFlatData:CubeMetadata>
            </igFlatData:FlatDataSource.CubesSettings>
            <igFlatData:FlatDataSource.HierarchyDescriptors>
                <igFlatData:HierarchyDescriptor SourcePropertyName="{x:Static local:TBARollBook.kMeasure}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Type"
                                                             LevelExpressionPath="Measure.Type"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="PM_NAME"
                                                HierarchyName="{x:Static local:TBARollBook.kFilterPM}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="All"/>
                        <igFlatData:HierarchyLevelDescriptor LevelName="PM"
                                                             LevelExpressionPath="PM_NAME"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="DELIVERY_DT"
                                                HierarchyName="{x:Static local:TBARollBook.kFilterDelivery}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="All"/>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Delivery"
                                                             LevelExpressionPath="DELIVERY_DT"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="ROLL_IND"
                                                HierarchyName="{x:Static local:TBARollBook.kFilterRoll}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Roll"
                                                             LevelExpressionPath="ROLL_IND"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="TURN_IND"
                                                HierarchyName="{x:Static local:TBARollBook.kFilterTurn}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Turn"
                                                             LevelExpressionPath="TURN_IND"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="PIMCO_DESC"
                                                HierarchyName="{x:Static local:TBARollBook.kViewProduct}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="All"/>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Product"
                                                             LevelExpressionPath="PIMCO_DESC"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
                <igFlatData:HierarchyDescriptor SourcePropertyName="BROKER"
                                                HierarchyName="{x:Static local:TBARollBook.kViewBroker}">
                    <igFlatData:HierarchyDescriptor.LevelDescriptors>
                        <igFlatData:HierarchyLevelDescriptor LevelName="All"/>
                        <igFlatData:HierarchyLevelDescriptor LevelName="Broker"
                                                             LevelExpressionPath="BROKER"/>
                    </igFlatData:HierarchyDescriptor.LevelDescriptors>
                </igFlatData:HierarchyDescriptor>
            </igFlatData:FlatDataSource.HierarchyDescriptors>
        </igFlatData:FlatDataSource>
  
  
  
   RollGrid.DataSource.Filters.Add(RollGrid.DataSource.CreateFilterViewModel(
                RollGrid.DataSource.Cube.Dimensions["PM_NAME"].Hierarchies.First()));
            FilterPM();

            RollGrid.DataSource.Filters.Add(RollGrid.DataSource.CreateFilterViewModel(
                RollGrid.DataSource.Cube.Dimensions["DELIVERY_DT"].Hierarchies.First()));
            FilterDelivery();

            RollGrid.DataSource.Filters.Add(RollGrid.DataSource.CreateFilterViewModel(
                RollGrid.DataSource.Cube.Dimensions["TURN_IND"].Hierarchies.First()));
            FilterTurn();

            RollGrid.DataSource.Filters.Add(RollGrid.DataSource.CreateFilterViewModel(
                RollGrid.DataSource.Cube.Dimensions["ROLL_IND"].Hierarchies.First()));
            FilterRoll();