# Statsig: Major incident: Feature Flag Evaluation Errors (Statsig)

**Summary:** Statsig’s major V2 Config Delivery API incident was recorded starting 2026-07-09 01:28 UTC and resolved after 1 h 8 min. Launched Feature Gates could return false instead of defaults between 20:56 UTC on July 8 and 01:40 UTC on July 9; V1 was unaffected. A config-spec generation change caused the issue; affected services were rolled back. _(machine-written, sol)_
- Kind: Major incident · Label: degradation (model (Jev))
- Changed: 2026-07-09 01:28 UTC · Detected: 2026-10-17 18:22 UTC
- [Source: https://stspg.io/6qwlh79gbd0r](https://stspg.io/6qwlh79gbd0r)
- [Company: Statsig](https://rewindex.com/company/statsig.md)
- Versions: before (none: first archived) → after incident\_version:208/mfzybgjxdqkq@139eff9df3c3
- Change 1 of 1 for this incident

## What changed

**1. Added: Title**

```diff
+ Feature Flag Evaluation Errors (Statsig)
```

**2. Added: Impact**

```diff
+ major
```

**3. Added: Status**

```diff
+ resolved
```

**4. Added: Start time**

```diff
+ 2026-07-09 01:28 UTC
```

**5. Added: Resolved time**

```diff
+ 2026-07-09 02:36 UTC
```

**6. Added: Affected components**

```diff
+ Asia Southeast 1, Config Delivery API - Asia Southeast 1, Config Delivery API - Europe West 1, Config Delivery API - US East 1, Config Delivery API - US East 5, Config Delivery API - US West 1, Europe West 1, US East 1, US East 5, US West 1
```

**7. Added: Update** (identified) · 2026-07-09 01:28 UTC

```diff
+ Since approximately 1:56 PM PT on July 8 (20:56 UTC on July 8), customers using the V2 Config Delivery API may have experienced incorrect evaluation of launched Feature Gates. Specifically, launched Gates may have returned false instead of their expected default value. Our team identified the root cause as a recent code change and started a rollback of the affected services. We were actively working to confirm that evaluations returned by the V2 Config Delivery API were again showing expected defaults for launched Gates. V1 consumers were not affected. At the time of this update, no immediate customer action was required. We would provide the next update as more information became available.
```

**8. Added: Update** (identified) · 2026-07-09 01:29 UTC

```diff
+ We are continuing to work on a fix for this issue.
```

**9. Added: Update** (identified) · 2026-07-09 01:35 UTC

```diff
+ We are continuing to work on a fix for this issue.
```

**10. Added: Update** (identified) · 2026-07-09 01:39 UTC

```diff
+ We are continuing to work on a fix for this issue.
```

**11. Added: Update** (monitoring) · 2026-07-09 02:15 UTC

```diff
+ A fix has been implemented and we are monitoring the results.
```

**12. Added: Update** (resolved) · 2026-07-09 02:36 UTC

```diff
+ Between approximately 20:56 UTC on July 8 and 01:40 UTC on July 9, customers using the V2 Config Delivery API may have experienced incorrect evaluation of launched Feature Gates. During this window, launched Gates could return false instead of their expected default. V1 consumers were not affected. We identified the root cause as a recent change to config-spec generation. We rolled back the affected services across all regions and regenerated config payloads. We have verified that launched Gates are again returning their expected defaults, and all Config Delivery API components are now operational. No action is required to restore correct evaluation going forward. However, if your systems persisted data or took actions based on evaluations returned by the V2 Config Delivery API during the impact window, we recommend reviewing and reconciling that downstream data, as affected launched Gates may have returned false during that time.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-07-09 01:28 UTC | Major incident: Feature Flag Evaluation Errors (Statsig) (this change) | degradation |

All Statsig changes: [timeline](https://rewindex.com/company/statsig/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._


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Canonical: https://rewindex.com/change/i0879813ddb516a · Markdown: https://rewindex.com/change/i0879813ddb516a.md · JSON: https://rewindex.com/api/v1/changes/i0879813ddb516a · Generated 2026-10-18T02:28:38.294Z