New react native element is not accessible

I'm working on react-native project (main target is iPhone 6) and got some problems with including new elements in accessibility chain. For some reasons Voice Over does not update when new element appears after re-rendering. The problem occurs only when app does something asynchronously. Here is my code:

export default class SmartView extends Component {
  constructor(props) {
    super(props)
    this.state = {
      showButton: false,
    }
  }

  showButton = () => {
    setTimeout(() => {
      this.setState({ showButton: true })
    }, 500)
  }

  render() {
    const { showButton } = this.state
    return (
      <View style={style.root}>
        <Button
          onPress={this.showButton}
          accessibilityRole="button"
          accessibilityTraits="button"
          accessibilityLabel="appeared"
          accessible
          simple
        >
          <Text>Appeared</Text>
        </Button>
        {showButton && (
          <Button
            accessibilityRole="button"
            accessibilityTraits="button"
            accessibilityLabel="appeared"
            accessible
            simple
          >
            <Text>Hidden</Text>
          </Button>
        )}
      </View>
    )
  }
}

So, if I remove setTimeout and do state updating in current js stream, everything work fine. Is there any possibility to make something like VoiceOverReload()?

I use: react-native v0.59.9 and iPhone 6, software version 12.4

Thanks.