Items in a list are unmounted if moved up but not if moved down

Description

https://github.com/user-attachments/assets/ada2ff0b-74d4-43c7-8afc-78830803998d

As visible from the video i have 2 text inputs rendered with a map with stable keys, i focus the one on top and then swap them and they swap keeping the focus on the active one which is what i need. If then i do the same but swapping the focused input from bottom to top it looses focus.

I dived a bit into the RN code and figured out that when going from bottom top top it gets unmounted and then remounted since Differentiator.cpp generated a remove and an insert commands. I understand nothing about how the diffing algo works so i have no idea if this is intendend behaviour or not but it's blocking me with this focus loss problem

I'm reporting the issue on iOS since is where i investigated it the most, on android it works bad as well but in a bit of a different way, with the same code i added in the reproduce section you can see the problem on android as well

Steps to reproduce

import { useState } from "react";
import { View, StyleSheet, TextInput, Button } from "react-native";

export default function TestPage() {
  const [keys, setKeys] = useState<string[]>(["1", "2"]);

  function swap() {
    const newKeys = [...keys];
    const temp = newKeys[0];
    newKeys[0] = newKeys[1];
    newKeys[1] = temp;
    setKeys(newKeys);
  }

  return (
    <View style={styles.container}>
      {keys.map((key, index) => (
        <TextInput
          key={key}
          style={styles.input}
          defaultValue={key == "1" ? "First input" : "Second input"}
        />
      ))}

      <Button title="Swap" onPress={swap} />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: "center",
    alignItems: "center",
  },
  input: {
    height: 40,
    width: "80%",
    borderColor: "gray",
    borderWidth: 1,
    marginBottom: 10,
    paddingHorizontal: 10,
  },
});

React Native Version

0.79.2

Affected Platforms

Runtime - Android, Runtime - iOS

Output of npx @react-native-community/cli info

System:
  OS: macOS 15.3.2
  CPU: (10) arm64 Apple M1 Pro
  Memory: 864.30 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 20.15.1
    path: ~/.nvm/versions/node/v20.15.1/bin/node
  Yarn:
    version: 1.22.22
    path: ~/.nvm/versions/node/v20.15.1/bin/yarn
  npm:
    version: 10.7.0
    path: ~/.nvm/versions/node/v20.15.1/bin/npm
  Watchman:
    version: 2025.04.28.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /Users/ipla/.rvm/gems/ruby-3.3.1/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.4
      - iOS 18.4
      - macOS 15.4
      - tvOS 18.4
      - visionOS 2.4
      - watchOS 11.4
  Android SDK:
    Android NDK: 22.1.7171670
IDEs:
  Android Studio: 2024.2 AI-242.23726.103.2422.12816248
  Xcode:
    version: 16.3/16E140
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 21.0.6
    path: /usr/bin/javac
  Ruby:
    version: 3.3.1
    path: /Users/ipla/.rvm/rubies/ruby-3.3.1/bin/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 19.0.0
    wanted: 19.0.0
  react-native:
    installed: 0.79.2
    wanted: 0.79.2
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Stacktrace or Logs

Doesn't apply

MANDATORY Reproducer

https://snack.expo.dev/@ipla/rn-swap-reproducer

Screenshots and Videos

https://github.com/user-attachments/assets/3ea384d0-5762-4fb3-bec1-7d677c316b3f

Beginne mit dem obligatorischen Snack-Reproducer und untersuche den React Native-Diffing-Pfad rund um Differentiator.cpp. Vergleiche dabei die generierten Befehle, wenn sich das fokussierte Eingabefeld in die jeweilige Richtung bewegt. Die Aufgabe ist abgeschlossen, wenn die beiden mit Keys versehenen TextInput-Elemente nach dem Austauschen in beide Richtungen unter iOS und Android den Fokus behalten, wie der Reproducer zeigt.