Branch link parameters not passed to app when opened via Google Search App

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Describe the bug

When a user clicks a Branch link from the Google Search App (GSA) on iOS, version >386, they are correctly redirected to the App Store and can install the app. However, after the app is installed and Branch SDK initializes, no attribution data is passed.
The Branch link contains multiple IDs, but none of them are delivered to the app. As a result, installs coming from GSA traffic appear as unattributed.

Steps to reproduce

1. Open a Branch link inside Google Search App (GSA) iOS, version >386.
2. Get redirected to the App Store.
3. Install the app and open it.
4. Observe that Branch SDK initializes but no attribution data (IDs from the link) is passed to the app.

Expected behavior

Branch SDK should handle attribution correctly when the user flow starts from the Google Search App. All data in the link should be passed to the app after installation, same as Safari or Chrome.

SDK Version

3.12.2

XCode Version

26.0.1

Device

iPhone 15 Pro Max

OS

18.6.2

Additional Information/Context

Example User-Agent:
Mozilla/5.0 (iPhone; CPU iPhone OS 18_5_0 like Mac OS X)
AppleWebKit/605.1.15 (KHTML, like Gecko)
GSA/**386.**3.809454442 Mobile/15E148 Safari/604.1

On Safari and Chrome, attribution works as expected.
On GSA, attribution fails — installs are recorded as organic/unattributed.
We can provide a list of full User-Agents that reproduce this issue.