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**Do you want to request a *feature* or report a *bug*?**
bug, I believe, unless I misunderstand how it works
**What is the current behavior?**
Given a `Suspense` inside `Suspense` case like
```
<Suspense fallback="Fallback 1">
  <LazyText1 text="First text" />
  <Suspense fallback="Fallback 2">
    <LazyText2 text="Second text!" />
  </Suspense>
</Suspense>
```

Promises in `LazyTexts` start resolving at the same time, but if `LazyText2` is resolved first it never renders, `Fallback 2` stays.

Result:
```
First text

Fallback 2
```

Please see https://codesandbox.io/s/234o4zry7n

**What is the expected behavior?**

Every `LazyText` displayed in the end
```
First text

Second text!
```

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
react, react-dom 16.6.0

state = {count: 0};
        render() {
          second = this;
          ReactTestRenderer.unstable_yield('SecondComponent');
          return null;
        }
      }
      advanceTimeBy(5);
      const renderer = ReactTestRenderer.create(
        <React.unstable_Profiler id="test" onRender={onRender}>
          <FirstComponent />
          <SecondComponent />
        </React.unstable_Profiler>,
        {unstable_isConcurrent: true},
      );
      
      renderer.unstable_flushAll(['FirstComponent', 'SecondComponent']);
      expect(onInteractionTraced).not.toHaveBeenCalled();
      expect(onInteractionScheduledWorkCompleted).not.toHaveBeenCalled();
      onRender.mockClear();
      advanceTimeBy(100);
      const interactionLowPri = {
        id: 0,
        name: 'lowPri',
        timestamp: mockNow(),
      };
      SchedulerTracing.unstable_trace(interactionLowPri.name, mockNow(), () => {
        
        first.setState({count: 1});