Not sure when this happened, but the feature got broken:

https://user-images.githubusercontent.com/29597/130155150-18fbca13-42d7-4d7d-831e-8db4a9672d94.mp4

Using the up/down arrows to navigate the list works fine, but jumping to the next/previous component with a warning or error doesn't quite work correctly. (The scroll offset is wrong so the component is often not visible.)
<React.Suspense fallback="Loading">
          <Child />
        </React.Suspense>
      );
      const container = document.createElement('div');
      utils.act(() => legacyRender(<Parent />, container));
      let renderer;
      utils.act(() => (renderer = TestRenderer.create(<Cont));
      expect(
        [root]
           
             ▾ <Suspense>
               ▾ <Child>
                 ▾ <Suspense>
                     <Grandchild>
      `);
      const outerSuspenseID = ((store.getElementIDAtIndex(1): any): number);
      const childID = ((store.getElementIDAtIndex(2): any): number);
      const innerSuspenseID = ((store.getElementIDAtIndex(3): any): number);
      utils.act(T_OWNER', payload: childID}));
      utils.act(() => renderer.
      expect(
        [owners]
        →  ▾ <Child>
             ▾ <Suspense>
                 <Grandchild>
      `);
      // Toggling a Suspense boundary inside of the flat list should update selected index
      utils.act(() =>
        dispatch({type: 'SELECT_ELEMENT_BY_ID', payload: innerSuspenseID}),