This is mainly focus on DateTime fields. They automatically create children name Day, Week and etc.They should be named “<parentName>.Day”

Only for local field description 

Add in LocalDataSourceFieldDescriptionsProvider property named FormatDisplayNameAsName which turn on/off this functionality 

((LocalDataSourceFieldDescriptionsProvider)((LocalDataSourceProvider)this.radPivotGrid1.DataProvider).FieldDescriptionsProvider).FormatDisplayNameAsFieldName= true