CSOM (HighTrust) SP2013 Group by aggregate giving duplicates

Question

Hi I've been reading about group by in SharePoint 2013 CSOM from this article here. https://piyushksingh.com/2016/11/21/retrieve-grouped-listitems-sharepoint

I've recently upgraded to 2013 and though to give his example a go. All seems to work fine however when I switched from a standard field to a lookup field then I got duplicates.

My code.

CamlQuery test = new CamlQuery();
            test.ViewXml = @"<View Scope='Recursive'>
   <Query>
        <GroupBy Collapse='TRUE' GroupLimit='300'>
            <FieldRef LookupId='TRUE' Name='Doc_x002e__x0020_Type_x003A_Section'/>
         </GroupBy >
        <Where>
          <And>
             <Eq>
                <FieldRef Name='RiO_x0020_ID' />
                 <Value Type='Text'>1000002</Value >
               </Eq>
               <Neq>
                  <FieldRef Name='_Status' />
                   <Value Type='Text'>Hidden</Value>
                 </Neq>
              </And >
           </Where >
    </Query>
           <ViewFields>
                 <FieldRef Name='Doc_x002e__x0020_Type_x003A_Section' />
           </ViewFields>
            <RowLimit paged='TRUE'>30</RowLimit>

                <Aggregations >
                      <FieldRef Name='Doc_x002e__x0020_Type_x003A_Section' Type='COUNT'/>
                     </Aggregations>
        </View>";



            test.FolderServerRelativeUrl = "/Drafts/Documents/1000002";
            //Idea for aggregations
            var l = _sp.Web.Lists.GetByTitle('Documents');
            var q = l.RenderListData(test.ViewXml);

            _sp.ExecuteQuery();

            return Content(q.Value);

And some of the response.

[{
"Doc_x002e__x0020_Type_x003A_Section": "Advanced Decisions\u002fStatements",
"ecb.dispex": "return DispEx(this,event,'TRUE','FALSE','','','1','','','','','2','1','','','','')",
"Doc_x002e__x0020_Type_x003A_Section.urlencoded": "%3B%23Advanced%20Decisions%2FStatements%3B%23",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.group": "1",
"Doc_x002e__x0020_Type_x003A_Section.newgroup": "1",
"Doc_x002e__x0020_Type_x003A_Section.groupindex": "1_",
"Doc_x002e__x0020_Type_x003A_Section.COUNT": "140",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.agg": "1"
}
,{
"Doc_x002e__x0020_Type_x003A_Section": "AHP - Acorn Further Education Centre",
"ecb.dispex": "return DispEx(this,event,'TRUE','FALSE','','','1','','','','','2','1','','','','')",
"Doc_x002e__x0020_Type_x003A_Section.urlencoded": "%3B%23AHP%20%2D%20Acorn%20Further%20Education%20Centre%3B%23",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.group": "3",
"Doc_x002e__x0020_Type_x003A_Section.newgroup": "1",
"Doc_x002e__x0020_Type_x003A_Section.groupindex": "2_",
"Doc_x002e__x0020_Type_x003A_Section.COUNT": "140",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.agg": "3"
}
,{
"Doc_x002e__x0020_Type_x003A_Section": "AHP - Acorn Further Education Centre",
"ecb.dispex": "return DispEx(this,event,'TRUE','FALSE','','','1','','','','','2','1','','','','')",
"Doc_x002e__x0020_Type_x003A_Section.urlencoded": "%3B%23AHP%20%2D%20Acorn%20Further%20Education%20Centre%3B%23",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.group": "3",
"Doc_x002e__x0020_Type_x003A_Section.newgroup": "",
"Doc_x002e__x0020_Type_x003A_Section.groupindex": "2_",
"Doc_x002e__x0020_Type_x003A_Section.COUNT": "140",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.agg": "3"
}
,{
"Doc_x002e__x0020_Type_x003A_Section": "AHP - Arts and Music Therapies",
"ecb.dispex": "return DispEx(this,event,'TRUE','FALSE','','','1','','','','','2','1','','','','')",
"Doc_x002e__x0020_Type_x003A_Section.urlencoded": "%3B%23AHP%20%2D%20Arts%20and%20Music%20Therapies%3B%23",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.group": "10",
"Doc_x002e__x0020_Type_x003A_Section.newgroup": "1",
"Doc_x002e__x0020_Type_x003A_Section.groupindex": "3_",
"Doc_x002e__x0020_Type_x003A_Section.COUNT": "140",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.agg": "10"
}
,{
"Doc_x002e__x0020_Type_x003A_Section": "AHP - Arts and Music Therapies",
"ecb.dispex": "return DispEx(this,event,'TRUE','FALSE','','','1','','','','','2','1','','','','')",
"Doc_x002e__x0020_Type_x003A_Section.urlencoded": "%3B%23AHP%20%2D%20Arts%20and%20Music%20Therapies%3B%23",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.group": "10",
"Doc_x002e__x0020_Type_x003A_Section.newgroup": "",
"Doc_x002e__x0020_Type_x003A_Section.groupindex": "3_",
"Doc_x002e__x0020_Type_x003A_Section.COUNT": "140",
"Doc_x002e__x0020_Type_x003A_Section.COUNT.agg": "10"
}