Multiple call to render item

It's a questiob but may turn out to be a bug.

Problem: _renderItems gets called thrice
How to replicate:

Following is the code to display a carousel in a very simple example:

import React, {PureComponent} from 'react'
import { ScrollView, Text, View, SafeAreaView,Platform, Dimensions, StyleSheet  } from 'react-native';
import Carousel from 'react-native-snap-carousel';

export default class SnapDemo extends PureComponent {

    constructor(props){
        super(props)
         this.state = {data: [{'num':1},{'num':2},{'num':3}]}
    }

    _renderItem (item) {
        console.log(item)
        return(<View key={item.item.num} style={{backgroundColor:'orange', height:100}}><Text>{item.item.num}</Text></View>)
    }

    render(){
       return(
            <SafeAreaView style={{height: 600}}>
           <Carousel
                  data={this.state.data}
                  renderItem={this._renderItem}
                  itemWidth={Dimensions.get('window').width * 0.85}
                  sliderWidth={Dimensions.get('window').width}
                  containerCustomStyle={{flex:1}}
                  removeClippedSubviews={true}
                  keyExtractor={(item, index) => index.toString()}
                  slideStyle={{ flex: 1 }}/>

        </SafeAreaView>
        )
    }
}

There are 2 problems:

1. RenderItems is getting called thrice
   Image

2. I see a virtualized key warning message despite official docs mentioning that explicit key isn't required to be specified
   Image

Start with the supplied React Native reproduction and trace the carousel's _renderItems calls and key handling. Compare the observed call count and virtualized-key warning with the component's current behavior; done means the cause is identified and the expected rendering and key behavior are documented or corrected.