diff --git a/packages/react-devtools-shared/src/__tests__/__snapshots__/store-test.js.snap b/packages/react-devtools-shared/src/__tests__/__snapshots__/store-test.js.snap
index 7264c7704d7e2..46e5f86aedc07 100644
--- a/packages/react-devtools-shared/src/__tests__/__snapshots__/store-test.js.snap
+++ b/packages/react-devtools-shared/src/__tests__/__snapshots__/store-test.js.snap
@@ -255,6 +255,82 @@ exports[`Store collapseNodesByDefault:false should support nested Suspense nodes
         <Component key="Unrelated at End">
 `;
 
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 8: first and third child are suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Component key="Unrelated at Start">
+      ▾ <Suspense>
+          <Loading key="Suspense 1 Fallback">
+      ▾ <Suspense>
+          <Component key="Suspense 2 Content">
+      ▾ <Suspense>
+          <Loading key="Suspense 3 Fallback">
+        <Component key="Unrelated at End">
+`;
+
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 9: parent is suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Loading key="Parent Fallback">
+`;
+
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 10: parent is suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Loading key="Parent Fallback">
+`;
+
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 11: all children are suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Component key="Unrelated at Start">
+      ▾ <Suspense>
+          <Loading key="Suspense 1 Fallback">
+      ▾ <Suspense>
+          <Loading key="Suspense 2 Fallback">
+      ▾ <Suspense>
+          <Loading key="Suspense 3 Fallback">
+        <Component key="Unrelated at End">
+`;
+
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 12: all children are suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Component key="Unrelated at Start">
+      ▾ <Suspense>
+          <Loading key="Suspense 1 Fallback">
+      ▾ <Suspense>
+          <Loading key="Suspense 2 Fallback">
+      ▾ <Suspense>
+          <Loading key="Suspense 3 Fallback">
+        <Component key="Unrelated at End">
+`;
+
+exports[`Store collapseNodesByDefault:false should support nested Suspense nodes: 13: third child is suspended 1`] = `
+[root]
+  ▾ <Wrapper>
+      <Component key="Outside">
+    ▾ <Suspense>
+        <Component key="Unrelated at Start">
+      ▾ <Suspense>
+          <Component key="Suspense 1 Content">
+      ▾ <Suspense>
+          <Component key="Suspense 2 Content">
+      ▾ <Suspense>
+          <Loading key="Suspense 3 Fallback">
+        <Component key="Unrelated at End">
+`;
+
 exports[`Store collapseNodesByDefault:false should support reordering of children: 1: mount 1`] = `
 [root]
   ▾ <Root>
diff --git a/packages/react-devtools-shared/src/__tests__/store-test.js b/packages/react-devtools-shared/src/__tests__/store-test.js
index 466c075928f81..d2e95073e8a6d 100644
--- a/packages/react-devtools-shared/src/__tests__/store-test.js
+++ b/packages/react-devtools-shared/src/__tests__/store-test.js
@@ -285,73 +285,61 @@ describe('Store', () => {
       );
       expect(store).toMatchSnapshot('7: only third child is suspended');
 
-      // FIXME: The rest of the test fails. This was introduced as part of
-      // the Lanes refactor. I'm fairly certain it's related to the layout of
-      // the Suspense fiber: we no longer conditionally wrap the primary
-      // children. They are always wrapped in an extra fiber.
-      //
-      // This landed in the new fork without triggering the test run
-      // because we don't run the DevTools tests against both forks. I only
-      // discovered the failure once I upstreamed the changes.
-      //
-      // Since this has been running in www for weeks without major issues, I'll
-      // defer fixing this to a follow up.
-      //
-      // const rendererID = getRendererID();
-      // act(() =>
-      //   agent.overrideSuspense({
-      //     id: store.getElementIDAtIndex(4),
-      //     rendererID,
-      //     forceFallback: true,
-      //   }),
-      // );
-      // expect(store).toMatchSnapshot('8: first and third child are suspended');
-      // act(() =>
-      //   agent.overrideSuspense({
-      //     id: store.getElementIDAtIndex(2),
-      //     rendererID,
-      //     forceFallback: true,
-      //   }),
-      // );
-      // expect(store).toMatchSnapshot('9: parent is suspended');
-      // act(() =>
-      //   ReactDOM.render(
-      //     <Wrapper
-      //       suspendParent={false}
-      //       suspendFirst={true}
-      //       suspendSecond={true}
-      //     />,
-      //     container,
-      //   ),
-      // );
-      // expect(store).toMatchSnapshot('10: parent is suspended');
-      // act(() =>
-      //   agent.overrideSuspense({
-      //     id: store.getElementIDAtIndex(2),
-      //     rendererID,
-      //     forceFallback: false,
-      //   }),
-      // );
-      // expect(store).toMatchSnapshot('11: all children are suspended');
-      // act(() =>
-      //   agent.overrideSuspense({
-      //     id: store.getElementIDAtIndex(4),
-      //     rendererID,
-      //     forceFallback: false,
-      //   }),
-      // );
-      // expect(store).toMatchSnapshot('12: all children are suspended');
-      // act(() =>
-      //   ReactDOM.render(
-      //     <Wrapper
-      //       suspendParent={false}
-      //       suspendFirst={false}
-      //       suspendSecond={false}
-      //     />,
-      //     container,
-      //   ),
-      // );
-      // expect(store).toMatchSnapshot('13: third child is suspended');
+      const rendererID = getRendererID();
+      act(() =>
+        agent.overrideSuspense({
+          id: store.getElementIDAtIndex(4),
+          rendererID,
+          forceFallback: true,
+        }),
+      );
+      expect(store).toMatchSnapshot('8: first and third child are suspended');
+      act(() =>
+        agent.overrideSuspense({
+          id: store.getElementIDAtIndex(2),
+          rendererID,
+          forceFallback: true,
+        }),
+      );
+      expect(store).toMatchSnapshot('9: parent is suspended');
+      act(() =>
+        ReactDOM.render(
+          <Wrapper
+            suspendParent={false}
+            suspendFirst={true}
+            suspendSecond={true}
+          />,
+          container,
+        ),
+      );
+      expect(store).toMatchSnapshot('10: parent is suspended');
+      act(() =>
+        agent.overrideSuspense({
+          id: store.getElementIDAtIndex(2),
+          rendererID,
+          forceFallback: false,
+        }),
+      );
+      expect(store).toMatchSnapshot('11: all children are suspended');
+      act(() =>
+        agent.overrideSuspense({
+          id: store.getElementIDAtIndex(4),
+          rendererID,
+          forceFallback: false,
+        }),
+      );
+      expect(store).toMatchSnapshot('12: all children are suspended');
+      act(() =>
+        ReactDOM.render(
+          <Wrapper
+            suspendParent={false}
+            suspendFirst={false}
+            suspendSecond={false}
+          />,
+          container,
+        ),
+      );
+      expect(store).toMatchSnapshot('13: third child is suspended');
     });
 
     it('should display a partially rendered SuspenseList', () => {
diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.new.js b/packages/react-reconciler/src/ReactFiberBeginWork.new.js
index cee8ae1f0fefe..1dd44dd32f284 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.new.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.new.js
@@ -2082,7 +2082,18 @@ function updateSuspenseFallbackChildren(
   };
 
   let primaryChildFragment;
-  if ((mode & BlockingMode) === NoMode) {
+  if (
+    // In legacy mode, we commit the primary tree as if it successfully
+    // completed, even though it's in an inconsistent state.
+    (mode & BlockingMode) === NoMode &&
+    // Make sure we're on the second pass, i.e. the primary child fragment was
+    // already cloned. In legacy mode, the only case where this isn't true is
+    // when DevTools forces us to display a fallback; we skip the first render
+    // pass entirely and go straight to rendering the fallback. (In Concurrent
+    // Mode, SuspenseList can also trigger this scenario, but this is a legacy-
+    // only codepath.)
+    workInProgress.child !== currentPrimaryChildFragment
+  ) {
     // In legacy mode, we commit the primary tree as if it successfully
     // completed, even though it's in an inconsistent state.
     const progressedPrimaryFragment: Fiber = (workInProgress.child: any);
diff --git a/packages/react-reconciler/src/ReactFiberBeginWork.old.js b/packages/react-reconciler/src/ReactFiberBeginWork.old.js
index 97541e23460d7..92c9e87d86067 100644
--- a/packages/react-reconciler/src/ReactFiberBeginWork.old.js
+++ b/packages/react-reconciler/src/ReactFiberBeginWork.old.js
@@ -2082,7 +2082,18 @@ function updateSuspenseFallbackChildren(
   };
 
   let primaryChildFragment;
-  if ((mode & BlockingMode) === NoMode) {
+  if (
+    // In legacy mode, we commit the primary tree as if it successfully
+    // completed, even though it's in an inconsistent state.
+    (mode & BlockingMode) === NoMode &&
+    // Make sure we're on the second pass, i.e. the primary child fragment was
+    // already cloned. In legacy mode, the only case where this isn't true is
+    // when DevTools forces us to display a fallback; we skip the first render
+    // pass entirely and go straight to rendering the fallback. (In Concurrent
+    // Mode, SuspenseList can also trigger this scenario, but this is a legacy-
+    // only codepath.)
+    workInProgress.child !== currentPrimaryChildFragment
+  ) {
     // In legacy mode, we commit the primary tree as if it successfully
     // completed, even though it's in an inconsistent state.
     const progressedPrimaryFragment: Fiber = (workInProgress.child: any);