[iOS] Touch events fire on underlying views while UIActivityViewController (Share Sheet) is presented

Description

⚠️ Physical device only. This bug does not reproduce on the iOS Simulator.

On physical iOS devices, when Share.share() or ActionSheetIOS.showShareActionSheetWithOptions() presents a UIActivityViewController, tapping outside the share sheet to dismiss it also triggers touch events on the underlying RN views. For example, tapping above the share sheet to close it will fire onPress on anyPressable, TouchableOpacity, or other touch target at that screen position. In native iOS apps, this dismiss tap is consumed and does not reach the content underneath.

Real-world impact:

This bug is currently active in major production React Native apps on physical devices. For example, in Bluesky and Shop (by Shopify), if a user opens the iOS Share Sheet and taps the background to dismiss it, they can accidentally trigger background actions (like navigating, liking a post, or tapping a button).

Suspected root cause:

RN's touch system (RCTTouchHandler) processes events independently from UIKit's responder chain. When a native view controller is presented over the RN view hierarchy, UIKit knows not to deliver touches to the background — but RN's parallel touch system is unaware of the presentation and continues dispatching events.

I believe this same root cause affects other native iOS overlays outside the RN view hierarchy that rely on "touch outside" behavior to close, for example:

• @expo/ui SwiftUI ContextMenu (https://github.com/expo/expo/issues/42068 — closed for lack of repro, but I've verified it on a physical device)
• Zeego DropdownMenu (https://github.com/nandorojo/zeego/issues/91 — incorrectly closed as "native iOS behavior"; native apps like Mail don't have this problem)

Steps to reproduce

1. Open the Snack on a physical iOS device (⚠️ this bug does NOT reproduce on Simulator — only real hardware)
2. Tap "Share.share()" to open the share sheet
3. Wait for the share sheet to fully present (~0.8 seconds)
4. Tap any touch target in the upper portion of the screen (Pressable, TouchableOpacity, etc.)
5. Expected: Touches blocked by the share sheet
6. Actual: "Tapped" alert fires — touch passes through to the underlying view

React Native Version

0.84.1

Affected Platforms

Runtime - iOS

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

System:
    OS: macOS 26.2
    CPU: (10) arm64 Apple M4
    Memory: 161.16 MB / 32.00 GB
    Shell:
      version: 3.2.57
      path: /bin/bash
  Binaries:
    Node:
      version: 22.22.1
      path: /Users/jaronheard/Library/Caches/fnm_multishells/33861_1774296117289/bin/node
    Yarn:
      version: 1.22.19
      path: /opt/homebrew/bin/yarn
    npm:
      version: 10.9.4
      path: /Users/jaronheard/Library/Caches/fnm_multishells/33861_1774296117289/bin/npm
    Watchman:
      version: 2025.04.14.00
      path: /opt/homebrew/bin/watchman
  Managers:
    CocoaPods:
      version: 1.16.2
      path: /opt/homebrew/lib/ruby/gems/3.4.0/bin/pod
  SDKs:
    iOS SDK:
      Platforms:
        - DriverKit 25.2
        - iOS 26.2
        - macOS 26.2
        - tvOS 26.2
        - visionOS 26.2
        - watchOS 26.2
    Android SDK: Not Found
  IDEs:
    Android Studio: Not Found
    Xcode:
      version: 26.3/17C529
      path: /usr/bin/xcodebuild
  Languages:
    Java:
      version: 17.0.11
      path: /usr/bin/javac
    Ruby:
      version: 3.4.2
      path: /opt/homebrew/opt/ruby/bin/ruby
  npmPackages:
    "@react-native-community/cli":
      installed: 20.1.0
      wanted: 20.1.0
    react:
      installed: 19.2.3
      wanted: 19.2.3
    react-native:
      installed: 0.84.1
      wanted: 0.84.1
    react-native-macos: Not Found
  npmGlobalPackages:
    "*react-native*": Not Found
  Android:
    hermesEnabled: true
    newArchEnabled: true
  iOS:
    hermesEnabled: true
    newArchEnabled: true

Stacktrace or Logs

N/A

MANDATORY Reproducer

https://snack.expo.dev/@jaronheard/da36c0

Screenshots and Videos

Bluesky	Shop (Shopify)	Reproducer Snack
Tap passes through share sheet and navigates to Profile tab	Tap passes through share sheet and triggers the favorite/like button	Tap passes through share sheet and fires Pressable onPress alert

物理的な iOS デバイスで必須の Snack 再現手順から始め、その後、RN の RCTTouchHandler と、issue で説明されている share sheet の表示経路を調査します。UIActivityViewController の外側をタップして閉じても、下にある Pressable または TouchableOpacity ビューで touch イベントが発生しなくなれば完了です。Simulator ではなく、実機で動作を確認してください。