API does not update relationships

[Lithl]

PATCH /api/v2/stories/:id

Specifically tested with the above endpoint, but the problem may affect other endpoints as well. relationships are not updated at all with the PATCH request. With the above endpoint, this largely means updating the story's tags and setting the prequel story.

[Lithl]

Just tested this endpoint again, attempting to set a story's prequel:

PATCH https://www.fimfiction.net/api/v2/stories/102705
{
  "data": {
    "type": "story",
    "attributes": {
      "title": "...",
      "short_description": "...",
      "description": "...",
      "completion_status": "incomplete",
      "content_rating": "teen"
    },
    "relationships": {
      "prequel": {
        "data": {
          "type": "story",
          "id": "60063"
        }
      }
    }
  }
}

The response:

{
  "errors": [{
    "status": "422",
    "title": "Unsupported attribute submitted",
    "detail": null,
    "code": 4226,
    "meta": {
      "attribute": "prequel"
    },
    "links": {
      "about": "https://www.fimfiction.net/developers/api/v2/docs/error-codes#4226"
    }
  }]
}

When this issue was created, there was no error response, the attempt simply did nothing.

[Lithl]

Update: Just tested, this PATCH request still produces the same error response.