Android zIndex bug

DummyScreen.js

import React, {Component} from 'react';
import {
    StyleSheet,
    View,
    Text,
} from 'react-native';

export default class DummyScreen extends Component {
    render() {
        return (
            <View style={styles.container}>
                <View style={styles.up}/>
                <View style={styles.down}>
                    <View style={styles.middle}>
                        <Text style={styles.title}>Text</Text>
                    </View>
                </View>
            </View>
        );
    }
}

const styles = StyleSheet.create({
    container: {
        backgroundColor: 'black',
        flex: 1,
    },
    up: {
        justifyContent: 'center',
        alignItems: 'center',
        paddingBottom: 60,
        backgroundColor: 'black',
        marginHorizontal: 20,
        position: 'relative',
        flex: 1,

    },
    down: {
        backgroundColor: '#F0F0F0',
        flex: 1,
    },
    middle: {
        backgroundColor: 'white',
        top: -40,
        marginHorizontal: 20,
    },
    title: {
        fontSize: 36,
        textAlign: 'center',
        marginTop: 20,
        marginBottom: 20,
    },
});