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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

reconcileChildFibers(
          workInProgress,
          currentFallbackChild,
          null,
          renderExpirationTime,
        );
         
        child = next = primaryChild;
      }
    } else {
       
       
      const currentPrimaryChild: Fiber = (current.child: any);
      if (nextDidTimeout) {
         
         
        const nextFallbackChildren = nextProps.fallback;
        const primaryChildFragment = createFiberFromFragment(
           
           
          null,
          mode,
          NoWork,
          null,
        );
        primaryChildFragment.effectTag |= Placement;
        primaryChildFragment.child = currentPrimaryChild;
        currentPrimaryChild.return = primaryChildFragment;
         
        const fallbackChildFragment = (primaryChildFragment.sibling = createFiberFromFragment(