Error: The response (403) did not contain the expected <turbo-frame id="tf-main"> and will be ignored. To perform a full page visit instead, set turbo-visit-control to reload.

## Error

```
The response (403) did not contain the expected and will be ignored. To perform a full page visit instead, set turbo-visit-control to reload.
```

## Stack trace

```
../node_modules/@hotwired/turbo/dist/turbo.es2017-esm.js:3650 in FrameController.throwFrameMissingError
../node_modules/@hotwired/turbo/dist/turbo.es2017-esm.js:3646 in FrameController.handleFrameMissingFromResponse
../node_modules/@hotwired/turbo/dist/turbo.es2017-esm.js:3567 in FrameController.loadFrameResponse
```

## Tracking Details
- **Project**: exercism-js
- **Sentry**: [Error: The response (403) did not contain the expected and will be ignored. To perform a full page visit instead, set turbo-visit-control to reload.](https://thalamus-ai.sentry.io/issues/145220149/)
- **Culprit**: FrameController.throwFrameMissingError(@hotwired/turbo/dist/turbo.es2017-esm)
- **First seen:** Sep 6, 2026

Start with the Sentry report and the @hotwired/turbo stack trace, especially FrameController.loadFrameResponse and the request returning 403 for the tf-main frame. Reproduce the response in exercism-js and trace which request produces it. Done means the reported Turbo frame error is resolved or the intended full-page fallback is verified.

Written by the indexing model from the issue text.