<!--
  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

instance = this;
          return (
            <React.Fragment>
              <Yield value="first" />
              {this.state.count}
              <Yield value="last" />
            </React.Fragment>
          );
        }
      }
      advanceTimeBy(1);
      const interactionCreation = {
        id: 0,
        name: 'creation event',
        timestamp: mockNow(),
      };
      const onRender = jest.fn();
      let renderer;
      SchedulerTracing.unstable_trace(
        interactionCreation.name,
        mockNow(),
        () => {
          renderer = ReactTestRenderer.create(
            <React.unstable_Profiler id="test-profiler" onRender={onRender}>
              <Example />
            </React.unstable_Profiler>,
            {
              unstable_isConcurrent: true,
            },