React Native Environment Info:
    System:
      OS: macOS High Sierra 10.13.4
      CPU: x64 Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz
      Memory: 29.36 MB / 16.00 GB
      Shell: 5.3 - /bin/zsh
    Binaries:
      Node: 9.8.0 - ~/.nvm/versions/node/v9.8.0/bin/node
      Yarn: 1.9.4 - /usr/local/bin/yarn
      npm: 5.6.0 - ~/.nvm/versions/node/v9.8.0/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 11.4, macOS 10.13, tvOS 11.4, watchOS 4.3
      Android SDK:
        Build Tools: 23.0.1, 23.0.2, 23.0.3, 24.0.0, 24.0.1, 24.0.2, 24.0.3, 25.0.0, 25.0.1, 25.0.2, 25.0.3, 26.0.0, 26.0.1, 26.0.2, 26.0.3, 27.0.0, 27.0.1, 27.0.2, 27.0.3
        API Levels: 23, 24, 25, 26, 27
    IDEs:
      Android Studio: 3.1 AI-173.4907809
      Xcode: 9.4.1/9F2000 - /usr/bin/xcodebuild
    npmPackages:
      react: 16.4.1 => 16.4.1 
      react-native: 0.56.0 => 0.56.0 
    npmGlobalPackages:
      react-native-cli: 2.0.1
      react-native-rename: 2.2.2

react-native init reproduce

 /**
 * @format
 * @flow
 */

import React, {Component} from 'react';
import {TextInput} from 'react-native';
type Props = {};
export default class App extends Component<Props> {
    render() {
        return (
                <TextInput
                    multiline={true}
                    numberOfLines={2}
                    editable={true}
                    style={{
                        margin:50,
                        lineHeight: 100,
                        borderWidth: 1,
                        marginBottom: 10
                    }}
                />
        );
    }
}