FlatList onEndReached being called multiple times [duplicate]

<FlatList
style = { ...}
data = {data}
initialNumToRender = {10}
onEndReachedThreshold = {0.1}
onMomentumScrollBegin = {() => {this.onEndReachedCalledDuringMomentum = false;}}
onEndReached = {() => {
    if (!this.onEndReachedCalledDuringMomentum) {
      this.retrieveMore();    // LOAD MORE DATA
      this.onEndReachedCalledDuringMomentum = true;
    }
  }
}
/>