Using initialScrollIndex with Flatlist will cause missing items with react native

[mihaibulic2]

Description

When using initialScrollIndex with react native, the first few items in the dataset will not get rendered. It is impossible to see these items, even by scrolling back up.

(note: this is just a refiling of this issue which was just ignored 😞 #30387)

Steps to reproduce

1. render <10 items with Flatlist
2. set scroll index

React Native Version

0.74.1

Affected Platforms

Runtime - Android

Output of npx react-native info

info Fetching system and libraries information...
System:
  OS: macOS 14.4
  CPU: (8) arm64 Apple M1
  Memory: 111.80 MB / 16.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.10.0
    path: ~/.nvm/versions/node/v20.10.0/bin/node
  Yarn:
    version: 1.22.19
    path: /opt/homebrew/bin/yarn
  npm:
    version: 10.2.3
    path: ~/.nvm/versions/node/v20.10.0/bin/npm
  Watchman:
    version: 2024.01.22.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /opt/homebrew/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK:
    API Levels:
      - "28"
      - "30"
      - "31"
      - "33"
      - "34"
    Build Tools:
      - 30.0.3
      - 33.0.0
      - 33.0.1
      - 34.0.0
    System Images:
      - android-33 | Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2023.2 AI-232.10300.40.2321.11567975
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.7
    path: /usr/bin/javac
  Ruby:
    version: 2.6.10
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 18.2.0
    wanted: 18.2.0
  react-native:
    installed: 0.74.1
    wanted: 0.74.1
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: false
iOS:
  hermesEnabled: true
  newArchEnabled: false

Stacktrace or Logs

none

Reproducer

https://snack.expo.io/@divone/initialscrollindex-does-not-show-all-items

Screenshots and Videos

No response

[github-actions]

⚠️	Missing Reproducible Example
ℹ️	We could not detect a reproducible example in your issue report. Please provide either: If your bug is UI related: a Snack If your bug is build/update related: use our Reproducer Template. A reproducer needs to be in a GitHub repository under your username.

[CalNicklin]

Have you tried adding the keyExtractor prop? I had a similar issue where I couldn't access first and last indices of a FlatList - needed to add the keyExtractor and it fixed it for me.