I have created a custom index (Sitecore 9 Update 1) using the below config, hoping that the index would contain documents only corresponding to the 3 included templates. However my index includes all documents under the root node and is not filtered by these included templates alone.
<?xml version="1.0" encoding="utf-8"?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:search="http://www.sitecore.net/xmlconfig/search/">
<sitecore role:require="Standalone or ContentDelivery or ContentManagement" search:require="solr">
<contentSearch>
<indexConfigurations>
<articleSolrIndexConfiguration type="Sitecore.ContentSearch.SolrProvider.SolrIndexConfiguration, Sitecore.ContentSearch.SolrProvider">
<initializeOnAdd>false</initializeOnAdd>
<fieldMap type="Sitecore.ContentSearch.SolrProvider.SolrFieldMap, Sitecore.ContentSearch.SolrProvider">
<typeMatches hint="raw:AddTypeMatch">
<typeMatch typeName="guidCollection" type="System.Collections.Generic.List`1[System.Guid]" fieldNameFormat="{0}_sm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="stringCollection" type="System.Collections.Generic.List`1[System.String]" fieldNameFormat="{0}_sm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="intCollection" type="System.Collections.Generic.List`1[System.Int32]" fieldNameFormat="{0}_im" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="guid" type="System.Guid" fieldNameFormat="{0}_s" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="id" type="Sitecore.Data.ID, Sitecore.Kernel" fieldNameFormat="{0}_s" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="shortid" type="Sitecore.Data.ShortID, Sitecore.Kernel" fieldNameFormat="{0}_s" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="text" type="System.String" fieldNameFormat="{0}_t" cultureFormat="_{1}" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="string" type="System.String" fieldNameFormat="{0}_s" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="int" type="System.Int32" fieldNameFormat="{0}_tl" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="bool" type="System.Boolean" fieldNameFormat="{0}_b" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="datetime" type="System.DateTime" fieldNameFormat="{0}_tdt" format="yyyy-MM-dd'T'HH:mm:ss.FFF'Z'" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="long" type="System.Int64" fieldNameFormat="{0}_tl" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="float" type="System.Single" fieldNameFormat="{0}_tf" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="double" type="System.Double" fieldNameFormat="{0}_td" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="stringArray" type="System.String[]" fieldNameFormat="{0}_sm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="intArray" type="System.Int32[]" fieldNameFormat="{0}_im" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="datetimeArray" type="System.DateTime[]" fieldNameFormat="{0}_dtm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
<typeMatch typeName="datetimeCollection" type="System.Collections.Generic.List`1[System.DateTime]" fieldNameFormat="{0}_dtm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
</typeMatches>
<fieldNames hint="raw:AddFieldByFieldName">
<field fieldName="__created_by" returnType="string" />
<field fieldName="__smallcreateddate" returnType="datetime" format="yyyy-MM-dd'T'HH:mm:ss'Z'" />
<field fieldName="__smallupdateddate" returnType="datetime" format="yyyy-MM-dd'T'HH:mm:ss'Z'" />
<field fieldName="__workflow_state" returnType="string" />
<field fieldName="extension" returnType="text" />
<field fieldName="title" returnType="text" />
</fieldNames>
<fieldTypes hint="raw:AddFieldByFieldTypeName">
<fieldType fieldTypeName="checkbox" returnType="bool" />
<fieldType fieldTypeName="date|datetime" returnType="datetime" />
<fieldType fieldTypeName="html|rich text|single-line text|multi-line text|text|memo|image|reference" returnType="text" />
<fieldType fieldTypeName="word document" returnType="text" />
<fieldType fieldTypeName="integer" returnType="long" />
<fieldType fieldTypeName="number" returnType="float" />
<fieldType fieldTypeName="icon|droplist|grouped droplist" returnType="string" />
<fieldType fieldTypeName="checklist|multilist|treelist|tree list|treelistex|tree list|multilist with search|treelist with search" returnType="stringCollection" />
<fieldType fieldTypeName="name lookup value list|name value list" returnType="stringCollection" />
<fieldType fieldTypeName="droplink|droptree|grouped droplink|tree" returnType="stringCollection" />
</fieldTypes>
</fieldMap>
<documentOptions type="Sitecore.ContentSearch.SolrProvider.SolrDocumentBuilderOptions, Sitecore.ContentSearch.SolrProvider">
<indexAllFields>false</indexAllFields>
<include hint="list:AddIncludedTemplate">
<ContentGroupPage>{A212D61B-69BB-41D2-9C21-2D2D534CAAB5}</ContentGroupPage>
<SimpleArticlePage>{A1C555D5-C991-4439-92F7-BF9B74217AB2}</SimpleArticlePage>
<BrandedArticlePage>{24EE12B5-CCBF-4810-ADF2-65E37274143C}</BrandedArticlePage>
</include>
<fields hint="raw:AddExcludedSpecialField">
<remove type="both">AllTemplates</remove>
<remove type="both">Created</remove>
<remove type="both">Editor</remove>
<remove type="both">Hidden</remove>
<remove type="both">Icon</remove>
<remove type="both">Links</remove>
<remove type="both">Updated</remove>
</fields>
</documentOptions>
<virtualFields type="Sitecore.ContentSearch.VirtualFieldProcessorMap, Sitecore.ContentSearch">
<processors hint="raw:AddFromConfiguration">
<add fieldName="daterange" type="Sitecore.ContentSearch.VirtualFields.DateRangeFieldProcessor, Sitecore.ContentSearch" />
<add fieldName="_lastestversion" type="Sitecore.ContentSearch.VirtualFields.LatestVersionFieldProcessor, Sitecore.ContentSearch" />
<add fieldName="updateddaterange" type="Sitecore.ContentSearch.VirtualFields.UpdatedDateRangeFieldProcessor, Sitecore.ContentSearch" />
<add fieldName="_url" type="Sitecore.ContentSearch.VirtualFields.UniqueIdFieldProcessor, Sitecore.ContentSearch" />
<add fieldName="_fullpath" type="Sitecore.ContentSearch.VirtualFields.FullPathFieldProcessor, Sitecore.ContentSearch" />
<add fieldName="parsedcreatedby_s" type="Sitecore.ContentSearch.VirtualFields.CreatedByFieldProcessor, Sitecore.ContentSearch" />
</processors>
</virtualFields>
<fieldReaders ref="contentSearch/indexConfigurations/defaultSolrIndexConfiguration/fieldReaders" />
<indexFieldStorageValueFormatter ref="contentSearch/indexConfigurations/defaultSolrIndexConfiguration/indexFieldStorageValueFormatter" />
<indexDocumentPropertyMapper ref="contentSearch/indexConfigurations/defaultSolrIndexConfiguration/indexDocumentPropertyMapper" />
<documentBuilderType ref="contentSearch/indexConfigurations/defaultSolrIndexConfiguration/documentBuilderType" />
<defaultSearchSecurityOption ref="contentSearch/indexConfigurations/defaultSearchSecurityOption" />
</articleSolrIndexConfiguration>
</indexConfigurations>
<configuration type="Sitecore.ContentSearch.ContentSearchConfiguration, Sitecore.ContentSearch">
<indexes hint="list:AddIndex">
<index id="Site_articles_index" type="Sitecore.ContentSearch.SolrProvider.SolrSearchIndex, Sitecore.ContentSearch.SolrProvider">
<param desc="name">$(id)</param>
<param desc="core">Site_articles_index</param>
<param desc="propertyStore" ref="contentSearch/indexConfigurations/databasePropertyStore" param1="$(id)" />
<configuration ref="contentSearch/indexConfigurations/articleSolrIndexConfiguration" />
<strategies hint="list:AddStrategy">
<strategy ref="contentSearch/indexConfigurations/indexUpdateStrategies/onPublishEndAsyncSingleInstance" />
</strategies>
<locations hint="list:AddCrawler">
<crawler type="Sitecore.ContentSearch.SitecoreItemCrawler, Sitecore.ContentSearch">
<Database>web</Database>
<Root>/sitecore/content/Site/Home</Root>
</crawler>
</locations>
<enableItemLanguageFallback>false</enableItemLanguageFallback>
<enableFieldLanguageFallback>false</enableFieldLanguageFallback>
</index>
</indexes>
</configuration>
</contentSearch>
Any ideas on what I am missing here?