<!--
  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

warnAboutUpdateOnUnmounted(fiber, false);
          break;
      }
    }
    return null;
  }
  if (enableSchedulerTracing) {
    const interactions = __interactionsRef.current;
    if (interactions.size > 0) {
      const pendingInteractionMap = root.pendingInteractionMap;
      const pendingInteractions = pendingInteractionMap.get(expirationTime);
      if (pendingInteractions != null) {
        interactions.forEach(interaction => {
          if (!pendingInteractions.has(interaction)) {
            // 
            interaction.__count++;
          }
          pendingInteractions.add(interaction);
        });
      } else {
        pendingInteractionMap.set(expirationTime, new Set(interactions));
        // 
        interactions.forEach(interaction => {
          interaction.__count++;
        });
      }
      const subscriber = __subscriberRef.current;
      if (subscriber !== null) {
        const threadID = computeThreadID(
          expirationTime,