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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

[true, false].forEach(
          replayFailedUnitOfWorkWithInvokeGuardedCallback => {
            describe(`replayFailedUnitOfWorkWithInvokeGuardedCallback ${
              replayFailedUnitOfWorkWithInvokeGuardedCallback
                ? 'enabled'
                : 'disabled'
            }`, () => {
              beforeEach(() => {
                jest.resetModules();
                loadModules({
                  replayFailedUnitOfWorkWithInvokeGuardedCallback,
                });
              });
              it('should accumulate actual time after an error handled by componentDidCatch()', () => {
                const callback = jest.fn();
                const ThrowsError = () => {
                  advanceTimeBy(3);
                  throw Error('expected error');
                };
                class ErrorBoundary extends React.Component {
                  state = {error: null};
                  componentDidCatch(error) {
                    this.setState({error});
                  }
                  render() {
                    advanceTimeBy(2);
                    return this.state.error === null ? (
                      this.props.children
                    ) : (
                      <AdvanceTime byAmount={20} />