One capture completed and preserved. Actual content was **800×450**. Source RAF measured **60 intervals in 1,000 ms: 60 fps**. Waited four seconds, clicked `div#n` once successfully, then stopped. Settings unchanged; no edits or tests.

`ffprobe -count_frames`: **212 frames**, **4.732500 s**, average rate **2120000/47589 ≈ 44.55 fps**, **49,862 bytes**.

Exact start response payload (`isError: false`):
```json
{
  "tabId": "tab_1_c0482162-5f84-4b60-be67-7d0dc745b3b5",
  "recording": true,
  "startedAt": "2026-10-22T23:25:48.358Z",
  "toolIcon": {
    "_tag": "website",
    "pageUrl": "http://127.0.0.1:19444/moving.html"
  }
}
```

Exact stop response payload (`isError: false`):
```json
{
  "id": "599d9937-c35a-488e-a9fc-69bb1b93b6c0-8932169a-7c16-4f93-91f4-bcb8676f4740-mp4",
  "tabId": "tab_1_c0482162-5f84-4b60-be67-7d0dc745b3b5",
  "path": "/home/ubuntu/wt/issue-19442/.t3-desktop/userdata/attachments/599d9937-c35a-488e-a9fc-69bb1b93b6c0-8932169a-7c16-4f93-91f4-bcb8676f4740-mp4.mp4",
  "mimeType": "video/mp4",
  "sizeBytes": 49862,
  "createdAt": "2026-10-22T23:25:53.068Z",
  "toolIcon": {
    "_tag": "website",
    "pageUrl": "http://127.0.0.1:19444/moving.html"
  }
}
```

![Independent moving-fixture capture at 800×450](/home/ubuntu/wt/issue-19442/.t3-desktop/userdata/attachments/599d9937-c35a-488e-a9fc-69bb1b93b6c0-8932169a-7c16-4f93-91f4-bcb8676f4740-mp4.mp4)