iOS Duplicate JS unhandled issues in new architecture

[gkartalis]

What React Native libraries do you use?

RN New Architecture, React Navigation, Hermes, Expo (mobile only)

Are you using sentry.io or on-premise?

sentry.io (SaS)

@sentry/react-native SDK Version

6.21.0

How does your development environment look like?

https://github.com/artsy/eigen

System:
  OS: macOS 26.1
  CPU: (12) arm64 Apple M2 Pro
  Memory: 411.53 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 24.6.0
    path: ~/.local/share/mise/installs/node/24.6.0/bin/node
  Yarn:
    version: 4.10.3
    path: ~/.local/share/mise/installs/yarn/4.10.3/bin/yarn
  npm:
    version: 11.5.1
    path: ~/.local/share/mise/installs/node/24.6.0/bin/npm
  Watchman:
    version: 2025.11.10.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /Users/georgioskartalis/.local/share/mise/installs/ruby/3.1.7/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 25.0
      - iOS 26.0
      - macOS 26.0
      - tvOS 26.0
      - visionOS 26.0
      - watchOS 26.0
  Android SDK:
    API Levels:
      - "30"
      - "34"
      - "35"
      - "36"
    Build Tools:
      - 33.0.1
      - 34.0.0
      - 35.0.0
      - 36.0.0
      - 36.1.0
    System Images:
      - android-30 | Google APIs ARM 64 v8a
      - android-34 | Google Play ARM 64 v8a
      - android-35 | Google Play ARM 64 v8a
      - android-35 | Pre-Release 16 KB Page Size Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2025.2 AI-252.25557.131.2521.14432022
  Xcode:
    version: 26.0.1/17A400
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.11
    path: /Users/georgioskartalis/.local/share/mise/installs/java/zulu-17.50.19.0/bin/javac
  Ruby:
    version: 3.1.7
    path: /Users/georgioskartalis/.local/share/mise/installs/ruby/3.1.7/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.0.0
    wanted: 20.0.0
  react:
    installed: 19.1.0
    wanted: 19.1.0
  react-native:
    installed: 0.81.5
    wanted: 0.81.5
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Sentry.init()

  Sentry.init({
    dsn: sentryDSN,
    release: eigenSentryReleaseName(),
    dist: eigenSentryDist(),
    enableAutoSessionTracking: true,
    autoSessionTracking: true,
    enableWatchdogTerminationTracking: false,
    attachStacktrace: true,
    tracesSampleRate: props.debug ? 1.0 : 0.05,
    profilesSampleRate: props.debug ? 1.0 : 0.05,
    debug: props.debug,
    integrations: [navigationInstrumentation],
    ...props,
  })

Steps to Reproduce

We started integrating new architecture in our app - still WIP but almost there.

The repro steps are basically triggering a manual JS crash on iOS :

       <DevMenuButtonItem
            title="Throw Sentry Error"
            onPress={() => {
              if (!Keys.secureFor("SENTRY_DSN")) {
                Alert.alert(
                  "No Sentry DSN available",
                  __DEV__ ? "Set it in keys.shared.json and re-build the app." : undefined
                )
                return
              }
              throw Error("Sentry test error")
            }}
          />

Expected Result

On iOS old architecture of react native we were getting one issue like this, after switching to the new one we would expect to see something similar but

Actual Result

On iOS new architecture when manaly triggering a JS Crash to test out sentry we are getting two errors for the JS crash, one as before (see here) and a duplicate one that looks like this:

C++ Exception:
N8facebook3jsi7JSErrorE: ExceptionsManager.reportException raised an exception: Unhandled JS Exception: Error: Sentry test error, stack: onPress@1:6324323 onPressWrapped@1:3248979 _performTransitionSideEffects@1:713425 ......

Note: Android is working as expected, the issue exists only in iOS

[linear]

RN-455

[antonis]

Thank you for the detailed report @gkartalis 🙇
We will investigate this and iterate back.

[antonis]

Heads up that we've shipped a fix for that in 7.9.0. Let us know if this didn't solve the problem 🙇