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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

}
        node = node.return;
      }
      node.sibling.return = node.return;
      node = node.sibling;
    }
  };
  
  const appendAllChildrenToContainer = function(
    containerChildSet: ChildSet,
    workInProgress: Fiber,
    needsVisibilityToggle: boolean,
    isHidden: boolean,
  ) {
    
    
    let node = workInProgress.child;
    while (node !== null) {
      
      branches: if (node.tag === HostComponent) {
        let instance = node.stateNode;
        if (needsVisibilityToggle) {
          const props = node.memoizedProps;
          const type = node.type;
          if (isHidden) {
            
            instance = cloneHiddenInstance(instance, type, props, node);
          } else {