diff --git a/packages/react-instantsearch/src/core/createInstantSearchManager.derived.test.js b/packages/react-instantsearch/src/core/createInstantSearchManager.derived.test.js
index 2dac87a1f1..9d3d3d3ac7 100644
--- a/packages/react-instantsearch/src/core/createInstantSearchManager.derived.test.js
+++ b/packages/react-instantsearch/src/core/createInstantSearchManager.derived.test.js
@@ -120,7 +120,82 @@ describe('createInstantSearchManager', () => {
           });
         });
       });
+
+      it('updates the store and searches with duplicate Index & SortBy', () => {
+        // <InstantSearch indexName="first">
+        //   <SearchBox defaultRefinement="query" />
+        //
+        //   <Index indexName="first">
+        //     <SortBy defaultRefinement="third" />
+        //   </Index>
+        //
+        //   <Index indexName="second" />
+        // </InstantSearch>;
+
+        const ism = createInstantSearchManager({
+          indexName: 'first',
+          initialState: {},
+          searchParameters: {},
+          algoliaClient: client,
+        });
+
+        // <SearchBox defaultRefinement="query" />
+        ism.widgetsManager.registerWidget({
+          getSearchParameters: params => params.setQuery('query'),
+          context: {},
+          props: {},
+        });
+
+        // <Index indexName="first" />
+        ism.widgetsManager.registerWidget({
+          getSearchParameters: x => x.setIndex('first'),
+          context: {},
+          props: {
+            indexName: 'first',
+          },
+        });
+
+        // <Index indexName="first">
+        //   <SortBy defaultRefinement="third" />
+        // </Index>
+        ism.widgetsManager.registerWidget({
+          getSearchParameters: x => x.setIndex('third'),
+          context: { multiIndexContext: { targetedIndex: 'first' } },
+          props: {},
+        });
+
+        // <Index indexName="second" />
+        ism.widgetsManager.registerWidget({
+          getSearchParameters: x => x.setIndex('second'),
+          context: {},
+          props: {
+            indexName: 'second',
+          },
+        });
+
+        expect(ism.store.getState().results).toBe(null);
+
+        ism.widgetsManager.update();
+
+        return Promise.resolve().then(() => {
+          jest.runAllTimers();
+
+          expect(ism.store.getState().results).toEqual({
+            first: {
+              index: 'third',
+              query: 'query',
+              page: 0,
+            },
+            second: {
+              index: 'second',
+              query: 'query',
+              page: 0,
+            },
+          });
+        });
+      });
     });
+
     describe('on external updates', () => {
       it('updates the store and searches', () => {
         const ism = createInstantSearchManager({
diff --git a/packages/react-instantsearch/src/core/createInstantSearchManager.js b/packages/react-instantsearch/src/core/createInstantSearchManager.js
index 5b8789d3b6..f4c64bd1ec 100644
--- a/packages/react-instantsearch/src/core/createInstantSearchManager.js
+++ b/packages/react-instantsearch/src/core/createInstantSearchManager.js
@@ -121,6 +121,8 @@ export default function createInstantSearchManager({
         sharedParameters
       );
 
+    indexMapping[mainIndexParameters.index] = indexName;
+
     return { sharedParameters, mainIndexParameters, derivatedWidgets };
   }
 
diff --git a/stories/MultiIndex.stories.js b/stories/MultiIndex.stories.js
index 0687b2f8bb..6a7931d6f3 100644
--- a/stories/MultiIndex.stories.js
+++ b/stories/MultiIndex.stories.js
@@ -7,6 +7,7 @@ import {
   Index,
   Highlight,
   SearchBox,
+  SortBy,
 } from '../packages/react-instantsearch/dom';
 import {
   connectHits,
@@ -62,6 +63,47 @@ stories
       <AutoComplete />
     </InstantSearch>
   ))
+  .add('with SortBy nested in same Index as Root', () => (
+    <InstantSearch
+      appId="latency"
+      apiKey="6be0576ff61c053d5f9a3225e2a90f76"
+      indexName="categories"
+    >
+      <SearchBox />
+
+      <div className="multi-index_content">
+        <div className="multi-index_categories-or-brands">
+          <Index indexName="categories">
+            <Configure hitsPerPage={3} />
+
+            <SortBy
+              defaultRefinement="categories"
+              items={[
+                { value: 'categories', label: 'Categories' },
+                { value: 'bestbuy', label: 'Best buy' },
+              ]}
+            />
+
+            <CustomCategoriesOrBrands />
+          </Index>
+
+          <Index indexName="products">
+            <Configure hitsPerPage={3} />
+
+            <SortBy
+              defaultRefinement="products"
+              items={[
+                { value: 'products', label: 'Products' },
+                { value: 'brands', label: 'Brands' },
+              ]}
+            />
+
+            <CustomCategoriesOrBrands />
+          </Index>
+        </div>
+      </div>
+    </InstantSearch>
+  ))
   .add('with conditional rendering', () => (
     <InstantSearch
       appId="latency"