<!--
  Note: if the issue is about documentation or the website, please file it at:
  https://github.com/reactjs/reactjs.org/issues/new
-->

**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

ReactNoop.yield('Foo');
      return (
        <Suspense fallback={<Text text="Loading..." />}>
          <Bar>
            <AsyncText text="A" ms={100} />
            <Text text="B" />
          </Bar>
        </Suspense>
      );
    }
    ReactNoop.render(<Foo />);
    expect(ReactNoop.flush()).toEqual([
      'Foo',
      'Bar',
      
      'Suspend! [A]',
      
      'B',
      'Loading...',
    ]);
    expect(ReactNoop.getChildren()).toEqual([]);
    
    await advanceTimers(50);
    
    expect(ReactNoop.flush()).toEqual([]);
    expect(ReactNoop.getChildren()).toEqual([]);