[sGTM Android] Events registered in GA4 but sGTM uploader returns count: 0 in SCION_UPLOAD

[denniszwier]

Environment

• Android Studio version: Android Studio Otter 3 Feature Drop | 2025.2.3
• Firebase Component: Analytics / GA4 / server-side Google Tag Manager
• Component version: Firebase bom version: 34.9.0

Problem

Steps to reproduce:

I am implementing Server-Side Google Tag Manager (sGTM) via the Firebase SDK. While standard Firebase Analytics events are successfully sent to GA4, the sGTM uploader consistently fails to include these events in its upload batches, even when Preview Mode is active.

1. Enable sGTM in the Android Manifest (google_analytics_sgtm_upload_enabled = true).
2. Configure a Server-side tagging URL in the GA4 Android Data Stream (100% traffic).
3. Launch the app via the sGTM Preview Intent (QR code/link).
4. Logs confirm [sgtm] Preview Mode was enabled with the correct key.
5. Trigger events (e.g., view_item, add_to_cart). Logs show events are registered.
6. Observe the SCION_UPLOAD job. It consistently returns count: 0.

Log Output:

[sgtm] Preview Mode was enabled. Using the sgtmPreviewKey: ZW52LTY2...
Passing event to registered event handler (FE): view_item, Bundle[{...}]
[sgtm] App Receiver notified batches are available
[sgtm] Scheduling Scion upload, millis: 1000
AppMeasurementJobService is starting up.
onStartJob received action: com.google.android.gms.measurement.SCION_UPLOAD
[sgtm] Started client-side batch upload work.
[sgtm] Getting upload batches from service (FE)
[sgtm] Got upload batches from service. count: 0
[sgtm] Completed client-side batch upload work. total, success: 0, 0

Standard GA4 events do arrive in the GA4 (Realtime) console, but no requests hit the sGTM endpoint or show up in the GTM Server Preview console.

AndroidManifest.xml

<activity
            android:name="com.google.firebase.analytics.GoogleAnalyticsServerPreviewActivity"
            android:exported="true"
            android:noHistory="true">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data android:scheme="tagmanager.sgtm.c.${applicationId}" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="google_analytics_sgtm_upload_enabled"
            android:value="true" />

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[lehcar09]

Hi @denniszwier, thank you for raising the issue. I'm trying to reproduce this issue and I saw the same logs with what you shared. However, I'm also seeing that the sGTM upload has been queued.

[sgtm] Sending sgtm batches available notification to app: com.google.dps
Stopping uploading service(s)
[sgtm] App Receiver notified batches are available
[sgtm] Scheduling Scion upload, millis: 1000
[sgtm] Scion upload job scheduled with result: SUCCESS
Application going to the background
Application backgrounded at: timestamp_millis: 1772251864387
[sgtm] Going background, trigger client side upload. appId: com.google.dps
AppMeasurementJobService is starting up.
onStartJob received action: com.google.android.gms.measurement.SCION_UPLOAD
[sgtm] Started client-side batch upload work.
[sgtm] Getting upload batches from service (FE)
[sgtm] batch skipped waiting for next retry. appId, rowId, lastUploadMillis: com.google.dps, 1, 1772245283477
[sgtm] batch skipped waiting for next retry. appId, rowId, lastUploadMillis: com.google.dps, 2, 1772245405375
[sgtm] batch skipped waiting for next retry. appId, rowId, lastUploadMillis: com.google.dps, 3, 1772246731330
[sgtm] batch skipped waiting for next retry. appId, rowId, lastUploadMillis: com.google.dps, 4, 1772251109172
[sgtm] batch skipped waiting for next retry. appId, rowId, lastUploadMillis: com.google.dps, 5, 1772251207091
[sgtm] Sending queued upload batches to client. appId, count: com.google.dps, 0
[sgtm] Got upload batches from service. count: 0
[sgtm] Completed client-side batch upload work. total, success: 0, 0
[sgtm] AppMeasurementJobService processed last Scion upload request.
onUnbind called for intent. action: null
AppMeasurementJobService is shutting down.
Inactivity, disconnecting from the service

Do you see similar logs on your side?