Inaccuracies in Google Ads Offline Conversion Tracking

Your Google Ads offline conversion data may be less reliable than you expect. During a detailed analysis of the system’s operation, two unexpected platform behaviors were discovered that could significantly affect the accuracy of your reporting:

• Conversions appearing in the wrong accounts: If you upload offline conversions for multiple ad accounts in a single batch, Google may count conversions in accounts that didn’t actually generate the corresponding clicks or calls.
• Successful uploads do not guarantee counted conversions: “Successful” or “#OK” statuses in the interface do not mean that Google has definitively accepted the conversion and that it will appear in your reports.

These issues make it difficult to determine exactly how many conversions Google actually counted and cast doubt on the accuracy of reporting across different accounts. After an extensive analysis of discrepancies and consultations with Google Support, we have prepared a detailed breakdown of the causes behind these anomalies and actionable steps to resolve them.

Uploading Conversions to Multiple Accounts Simultaneously

Many marketing agencies and large brands (for example, national retailers managing separate online stores or sub-brands under a single MCC manager account) import offline conversions into multiple ad accounts via a single upload. This is a logical solution that saves time and reduces operational load compared to splitting files for each account individually.

Historically, Google would only accept an uploaded GCLID (Google Click Identifier) or phone number in the account that directly generated the click or call, rejecting it for all others.

However, the algorithm has now changed. If you use the same conversion action name (e.g., “Purchase” or “Qualified Lead”) across different accounts, Google may accept a conversion in an account that had nothing to do with generating that click or call.

This problem was discovered using the example of a multi-brand advertiser with standalone Google Ads accounts for each brand under a unified manager account. Sales data was sent to Google via offline conversion imports, with each account featuring a conversion action bearing the exact same name. During analytics reconciliation, it became clear that specific GCLIDs were somehow being duplicated and accepted by multiple ad accounts simultaneously.

After lengthy discussions with Google Support, an official response was received: this is expected system behavior. If you upload a GCLID or phone number to an account, and the conversion action name in the file matches the name in that account, Google can approve the upload even if the click occurred in another campaign within a different account.

Does this lead to overcounting?

Yes. In the UI of certain accounts, you can see conversions tied to specific campaigns, even though those campaigns did not physically generate them.

Does this affect Smart Bidding?

According to Google Support, these “false” conversions are not factored into Smart Bidding algorithms, and conversion credit goes only to the campaign that generated the click. In practice, however, these conversions appear in the “Conversions” column and directly impact the Cost Per Acquisition (CPA) calculation in reports. Independently confirming whether they affect the learning of automated bidding strategies is currently impossible.

Does this happen with every uploaded conversion?

No. In many cases, Google still returns an error message stating that the conversion was rejected because the click was not associated with the account. The algorithm dictating when Google accepts these conversions and when it does not remains opaque.

How to Fix Tracking Issues

To prevent offline conversions from being attributed to the wrong accounts, marketers and analysts should implement one of the following three strategies:

1. Segment import files: Separate your databases and upload conversions exclusively to the ad account that generated them.
2. Unique conversion naming: Assign a unique name to the conversion action in each account (e.g., “Purchase_Brand_A”, “Purchase_Brand_B”) and use the corresponding names in your import files.
3. Cross-account conversion tracking: Set up unified conversion tracking at the manager account (MCC) level instead of creating local conversion actions within each child account.

Why ‘Successful’ and ‘#OK’ Statuses Do Not Guarantee Results

When you upload offline conversions, Google returns a status indicating upload recognition.

• In the online interface, you will see a “Successful” status.
• In the downloaded report, it will show “#OK”.

Previously, marketers reasonably assumed this status meant unconditional acceptance of the conversion by the system. However, as Google Support clarified, the initial upload validation only checks three basic things:

1. Correct file structure.
2. Existence of the specified conversion action in the account.
3. Correct GCLID format.

Full attribution verification happens much later. Therefore, the “#OK” status in the upload history only proves that the row was readable. It does not mean the conversion will be counted in final statistics. Often, the number of conversions actually displayed in the account is significantly lower than the number of rows marked “#OK”.

Why does Google recognize but not count a conversion?

Support provides two main explanations for potential discrepancies:

• The conversion is a duplicate (e.g., you accidentally uploaded the same GCLID multiple times).
• The conversion is associated with a click that Google deemed invalid (fraud, accidental clicks, etc.).

How to Properly Verify Accepted Conversions

Do not rely solely on the upload status. If you upload 100 conversions (for example, statuses from a CRM system) and Google marks 90 of them as “Successful”, it creates an illusion of a 90% acceptance rate. But if only 60 conversions ultimately appear in the ad account, your real successful import rate is 60%, meaning the algorithms are missing critical data.

Solution: Regularly reconcile the number of uploaded offline conversions against the conversions actually appearing in the ad account. Keep in mind that in standard reporting columns, Google attributes a conversion to the date of the click, not the date the conversion occurred. Therefore, daily figures may not match exactly, especially in niches with a long decision-making cycle (like real estate or B2B services).

Google Updates on Attribution and Import Authorization

Recently, the Google Ads Developer Blog announced improvements to the offline conversion import process, which rolled out during April and May of this year (without breaking API compatibility). Key changes include:

• Improved attribution and fallback recovery: Google has started attributing some expired GCLIDs and clicks that occurred before the conversion itself. This should reduce EXPIRED_EVENT and CONVERSION_PRECEDES_EVENT errors.
• Flexible import requests: The authorization structure has changed. It is now easier for manager (MCC) or client accounts to import conversions on behalf of other accounts. This is expected to decrease UNAUTHORIZED_CUSTOMER and INVALID_CUSTOMER_FOR_CLICK errors, potentially increasing overall attribution rates.

Recommendations for Daily Operations

The unexpected behavior of the offline conversion tracking system makes data verification a critical stage in a performance marketer’s workflow. Given that conversions can “settle” in the wrong accounts and successful upload statuses do not equal actual report data, we recommend adhering to the following rules:

1. Upload strictly new, previously unimported conversions.
2. Maintain a strict internal log of the unique GCLIDs you submit to the system.
3. Conduct regular data reconciliation between your CRM and the Google Ads interface, focusing on conversion time.

Until Google makes the import process more transparent, the core rule remains unchanged: never automatically assume that a “Successful” status guarantees 100% analytical accuracy.

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