There is a common problem while working with FlatList pagination. It calls two times with out any reason. We can solve it in different ways.But I have a very effect way which is worked for me.
Try to implement onMomentumScrollBegin on FlatList :
constructor(props) {
super(props);
this.onEndReachedCalledDuringMomentum = true;
}
<FlatList
...
onEndReached={this.onEndReached.bind(this)}
...