[Android 16][Fabric] Crash: java.lang.IllegalStateException: addViewAt: failed to insert view during GistModalActivity transition

[ankitminhas-aspire]

SDK version: 4.2.5

Environment: Production

Are logs available?
Yes. Detailed Datadog stack trace and lifecycle breadcrumbs are included below.

Describe the bug
A fatal java.lang.IllegalStateException occurs on Android 16 when using the New Architecture (Fabric). The crash happens specifically during the transition when an In-App message (Gist) is being mounted over a React Native surface.

The error addViewAt: failed to insert view [48] into parent [50] indicates that the Fabric renderer is attempting to attach a view that is already attached to another parent. This is a synchronization conflict between the Gist engine and the Fabric Mounting Manager.

To Reproduce

Enable New Architecture (Fabric) in a React Native app.

Target Android 16.

Use version 4.2.5 of the SDK.

triggers an In-App Message before opening the app.

As the app navigates or mounts a view (e.g., "Dashboard"), the GistModalActivity launches to show the message.

The app crashes with java.lang.IllegalStateException. This is from sentry logs we are not able to reproduce at our end but many sentry logs

Exception - This event
error
RuntimeException: Exception thrown when executing UIFrameGuarded

Device Orientation
info
{
  position: portrait
}

Ui Lifecycle
info
{
  screen: MainActivity,
  state: resumed
}

Ui Lifecycle
info
{
  screen: GistModalActivity,
  state: paused
}

Expected behavior
The In-App Message modal should mount and display without conflicting with the React Native Fabric view hierarchy.

Screenshots
NA

Additional context
The crash occurs immediately after the GistModalActivity reaches the resumed state. According to our Datadog breadcrumbs, the timeline is:

MainActivity pauses.

GistModalActivity is created/started/resumed.

Assets (tasks.svg, search.svg) are fetched for the modal.

The UI thread crashes while executing FabricUIManager.scheduleMountItem.

Stack Trace

java.lang.IllegalStateException: addViewAt: failed to insert view [48] into parent [50] at index 0

at com.facebook.react.fabric.mounting.SurfaceMountingManager.addViewAt(Unknown Source:249)
at com.facebook.react.fabric.mounting.mountitems.IntBufferBatchMountItem.execute(Unknown Source:255)
at com.facebook.react.fabric.mounting.MountItemDispatcher.executeOrEnqueue(Unknown Source:53)
...

Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.

at android.view.ViewGroup.addViewInner(ViewGroup.java:5539)
at com.facebook.react.views.view.ReactClippingViewManager.addView(SourceFile:6)
at com.facebook.react.fabric.mounting.SurfaceMountingManager.addViewAt(Unknown Source:196)

[mrehan27]

Thanks for the detailed report @ankitminhas-aspire, and sorry for the inconvenience this may have caused.

The version (4.2.5) you're using is quite old and does not utilize React Native's New Architecture and lacks support for Android 16 (which you mentioned). For reference:

• We started utilizing React Native's New Architecture (Fabric) in 4.6.0
• Android 16 support was added in 5.1.0
• Old Architecture support was fully removed in 6.0.0

It's possible this issue has already been addressed in newer versions. Can you please try upgrading to the latest (6.4.2) and let us know if you still encounter it?

I understand you're not able to reliably reproduce this yet, but if you come across any additional clues, that would really help. In particular, details around other libraries that might be causing conflicts, or any custom MainActivity configurations (e.g., android:configChanges, android:launchMode, etc.), could help us narrow this down.

Thanks again for the report, I'll keep this open while you try the upgrade. Have a great day.

[ankitminhas-aspire]

Thanks @mrehan27 , Will update version and monitor

[ankitminhas-aspire]

Thanks @mrehan27 , Will update version and monitor

Hi @mrehan27 , we updated to v6.4.2 but are unfortunately still seeing the same issue.
A few important notes:

• The issue is strictly happening on Android.
• It triggers exactly when the user closes the in-app notification and the gist://close action is fired.
• We still cannot reproduce it consistently locally; it seems random and might be limited to specific device speeds or transition timings under Fabric.

Looking at the latest Sentry logs, the timeline confirms the crash happens right as the modal tries to close:

• GistModalActivity state changes to paused.
• MainActivity state changes to resumed.
• App immediately fatals with RuntimeException: Exception thrown when executing UIFrameGuarded.

To answer your previous question regarding our MainActivity configuration, we are using standard React Native defaults:

• android:launchMode="singleTask"
• android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|screenSize|smallestScreenSize|uiMode"

One theory we are investigating: In our JS listener for messageActionTaken, we previously called CustomerIO.inAppMessaging.dismissMessage() even when the action was gist://close. Could invoking the JS dismiss method simultaneously with the native gist://close action cause a "double-unmount" collision in Fabric's SurfaceMountingManager?

[mrehan27]

Hi @ankitminhas-aspire, thanks for the update, and sorry to hear you're still facing this issue. I tried reproducing this by calling dismissMessage inside messageActionTaken for all messages but I still wasn't able to reproduce the crash on my end. To help us narrow this down further, could you please help with the following:

• Share any additional or complete logs that might help identify the root cause. Please remove any sensitive information before posting publicly, or feel free to send them to win@customer.io instead (with a link to this ticket for reference).
• Share the exact versions you're using for any relevant dependencies, such as: React Native, Expo, react-native-screens, react-navigation/* (and whether you're using Native Stack), react-native-reanimated, react-native-gesture-handler, or any other modal/navigation related libraries
• Any device specific details you've noticed such as particular manufacturers, models, or Android versions other than 16 where this happens more often.
• Just to confirm, are you still seeing this after the dismissMessage update you just mentioned?
• What's the crash frequency like? Is this happening consistently, occasionally, or very rarely?
• If possible, could you also try updating any outdated dependencies? That would help rule out conflicts caused by older libraries or legacy code.

I completely understand that you haven't been able to reproduce this reliably yet. The challenge on our side is that without a reproducible case or a clearer signal around the root cause, it's difficult to validate which fix would actually address the problem safely. If you're eventually able to reproduce it, it would really help if you could either:

• Share a minimal sample app, or
• Try reproducing it using our example app from the SDK repo and share the branch/changes with us

That would make it much easier for us to investigate and validate a fix properly. Thanks again for all the details and help so far.