title: Admob reward ads don't work on ios on Expo App
body: <p>On App.js I have initialized AdMobRewarded as following:</p>
  <pre><code>if (Platform.OS === 'ios') {
    AdMobRewarded.setAdUnitID('ca-app-pub-xxx/xxx');
  } else {
    AdMobRewarded.setAdUnitID('ca-app-pub-xxx/xxx');
  }
  </code></pre>
  <p>And here is the class:</p>
  <pre><code>export default class App extends React.Component {
    state = {
      fontsLoaded: false,
    };
  
    render() {
      const { fontsLoaded } = this.state;
      if (!fontsLoaded) {
        return (
          &lt;AppLoading
            startAsync={fetchFonts}
            onFinish={() =&gt; this.setState({ fontsLoaded: true })}
          /&gt;
        );
      }
      return (
        &lt;Provider store={store}&gt;
          &lt;AppContainer
            ref={navigatorRef =&gt; {
              NavigationService.setTopLevelNavigator(navigatorRef);
            }}
          /&gt;
          &lt;CommonComponents /&gt;
        &lt;/Provider&gt;
      );
    }
  }
  </code></pre>
  <p>Inside the CommonComponents I have put the listener for AdMobRewarded:</p>
  <pre><code>useEffect(() =&gt; {
    AdMobRewarded.addEventListener('rewardedVideoDidRewardUser', () =&gt; {
      setState({
        hintModalVisible: true,
        adIsLoading: false,
        mainMenuVisible: false,
      });
    });
  
    return () =&gt; {
      AdMobRewarded.removeAllListeners();
    };
  }, []);
  </code></pre>
  <p>setState is actually not React setState, it's a redux action I have implemented:</p>
  <pre><code>const setStateAction = (obj, sceneName) =&gt; {
    const type = sceneName ? `${sceneName}_SET_STATE` : 'SET_STATE';
    return { ...obj, type };
  };
  </code></pre>
  <p>Without the <code>rewardedVideoDidRewardUser</code> listener, calling <code>setState</code> does open the Modal and everything is fine.</p>
  <p><code>hintModalVisible</code> is used for Modal <code>isVisible</code> prop, which opens and closes the Modal.</p>
  <p>On Android everything works as expected, but there is a strange behavior on iOS. The ad shows for a second and automatically closes, and the Hint Modal doesn't open.</p>
  <p>Here is the function that requests and shows the ad. It is present in all screens of the app:</p>
  <pre><code>showHint = async () =&gt; {
    const { setState } = this.props;
    try {
      setState({
        mainMenuVisible: false,
      });
      await AdMobRewarded.requestAdAsync();
      await AdMobRewarded.showAdAsync();
    } catch (e) {
      setState({
        hintModalVisible: true,
        mainMenuVisible: false,
      });
    }
  };
  </code></pre>
  <p>It's an open source project, so you can the code <a href="https://github.com/xxmuaddib/rn-adventures-generator" rel="nofollow noreferrer">here</a></p>