react-native: zIndex is broken across ScrollViews

🐛 Bug Report

zIndex is broken when you have a ScrollView between your two different zIndexes. For example, given code like

render() {
    return <View style={styles.background}>
        <View style={styles.redBox}></View>
        <View>
            <View style={styles.greenBox}></View>
        </View>
    </View>
}

let styles = StyleSheet.create({
    background: {
        backgroundColor: "blue",
        height: "100%"
    },
    greenBox: {
        backgroundColor: "green",
        width: 100,
        height: 100,
        zIndex: 2
    },
    redBox: {
        height: 300,
        width: 300,
        backgroundColor: "red",
        position: "absolute",
        top: 0,
        left: 0,
        zIndex: 1
    },
});

you get a view that makes sense, blue background, then red box, then green box on top.

However, if you just switch the container of the green box to a ScrollView, the zIndex breaks:

<View style={styles.background}>
   <View style={styles.redBox}></View>
   <ScrollView>
        <View style={styles.greenBox}></View>
    </ScrollView>
</View>

Expected Behavior

Components inside of a ScrollView should still respect zIndex.

Code Example

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

export default class App extends Component {
    render() {
        return (
            <View style={styles.background}>
                <View style={styles.redBox}></View>
                <ScrollView>
                    <View style={styles.greenBox}></View>
                </ScrollView>
            </View>
        );
    }
}

let styles = StyleSheet.create({
    background: {
        backgroundColor: "blue",
        height: "100%"
    },
    greenBox: {
        backgroundColor: "green",
        width: 100,
        height: 100,
        zIndex: 2
    },
    redBox: {
        height: 300,
        width: 300,
        backgroundColor: "red",
        position: "absolute",
        top: 0,
        left: 0,
        zIndex: 1
    },
});

Environment

Environment: OS: Windows 10 Node: 9.3.0 Yarn: 1.3.2 npm: 4.6.1 Watchman: Not Found Xcode: N/A Android Studio: Version 3.2.0.0 AI-181.5540.7.32.5056338

Packages: (wanted => installed) react: 16.3.2 => 16.3.2 react-native: ^0.55.4 => 0.55.4

It’s worth noting that on iOS not even the working example I give here works, it doesn’t show the green box above the red one ever.