diff --git a/src/renderers/dom/fiber/__tests__/ReactDOMFiber-test.js b/src/renderers/dom/fiber/__tests__/ReactDOMFiber-test.js
index 990ad069d1e1..c91f05a4e59c 100644
--- a/src/renderers/dom/fiber/__tests__/ReactDOMFiber-test.js
+++ b/src/renderers/dom/fiber/__tests__/ReactDOMFiber-test.js
@@ -993,5 +993,18 @@ describe('ReactDOMFiber', () => {
         'leave parent', // Only when we leave the portal does onMouseLeave fire.
       ]);
     });
+
+    it('keeps track of namespaces despite low priority bailout', () => {
+      assertNamespacesMatch(
+        <svg {...expectSVG}>
+          {/*
+            TODO: this relies on the magic `hidden` attribute in Fiber.
+            Figure out a better test.
+          */}
+          <foreignObject hidden={true} {...expectSVG} />
+          <image {...expectSVG} />
+        </svg>
+      );
+    });
   }
 });
diff --git a/src/renderers/shared/fiber/__tests__/ReactIncremental-test.js b/src/renderers/shared/fiber/__tests__/ReactIncremental-test.js
index 9bf334b2080a..4175c8135651 100644
--- a/src/renderers/shared/fiber/__tests__/ReactIncremental-test.js
+++ b/src/renderers/shared/fiber/__tests__/ReactIncremental-test.js
@@ -1650,6 +1650,31 @@ describe('ReactIncremental', () => {
       'ShowBoth {"locale":"en","route":"/about"}',
       'ShowBoth {"locale":"en"}',
     ]);
+
+    ops.length = 0;
+    ReactNoop.render(
+      <Intl locale="zh">
+        <ShowLocale />
+        <Router route="/about">
+          <Indirection />
+        </Router>
+        <ShowBoth />
+      </Intl>
+    );
+    ReactNoop.flush();
+    expect(ops).toEqual([
+      'Intl {}',
+      'ShowLocale {"locale":"zh"}',
+      'Router {}',
+      'Indirection {}',
+      'ShowLocale {"locale":"zh"}',
+      'ShowRoute {"route":"/about"}',
+      'ShowNeither {}',
+      'Intl {}',
+      'ShowBoth {"locale":"ru","route":"/about"}',
+      'ShowBoth {"locale":"zh","route":"/about"}',
+      'ShowBoth {"locale":"zh"}',
+    ]);
   });
 
   it('does not leak own context into context provider', () => {