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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

expect(onInteractionTraced).toHaveBeenLastNotifiedOfInteraction(
        interaction,
      );
      expect(onInteractionScheduledWorkCompleted).not.toHaveBeenCalled();
      expect(getWorkForReactThreads(onWorkStarted)).toHaveLength(0);
      expect(getWorkForReactThreads(onWorkStopped)).toHaveLength(0);
      expect(onRender).not.toHaveBeenCalled();
      renderer.unstable_flushAll(['Child:1']);
      expect(onRender).toHaveBeenCalledTimes(1);
      let call = onRender.mock.calls[0];
      expect(call[0]).toEqual('test-profiler');
      expect(call[6]).toMatchInteractions(
        ReactFeatureFlags.enableSchedulerTracing ? [interaction] : [],
      );
      expect(onInteractionTraced).toHaveBeenCalledTimes(1);
      expect(onInteractionScheduledWorkCompleted).toHaveBeenCalledTimes(1);
      expect(
        onInteractionScheduledWorkCompleted,
      ).toHaveBeenLastNotifiedOfInteraction(interaction);
      expect(getWorkForReactThreads(onWorkStarted)).toHaveLength(1);
      expect(getWorkForReactThreads(onWorkStarted)[0][0]).toMatchInteractions([
        interaction,
      ]);
      expect(getWorkForReactThreads(onWorkStopped)).toHaveLength(1);
      expect(getWorkForReactThreads(onWorkStopped)[0][0]).toMatchInteractions([
        interaction,
      ]);
    });
    describe('suspense', () => {
      function awaitableAdvanceTimers(ms) {