(*models.Error) is not supported by the TextConsumer

When creating a site using the Netlify terraform provider, I get this error:

&{0 } (*models.Error) is not supported by the TextConsumer, can be resolved by supporting TextUnmarshaler interface

I attempted to create the site via cURL to get more visibility into the API response:

Request

curl -X POST \
  https://api.netlify.com/api/v1/sites \
  -H 'Authorization: Bearer <secret>' \
  -H 'Content-Type: application/json' \
  -d '{
	"name": "test",
	"repo": {
		"provider": "github",
		"repo_path": "jaredpiedt/test",
		"repo_branch": "master"
	}
}'

Response

HTTP/1.1 422 Unprocessable Entity

{
    "errors": {
        "subdomain": [
            "must be unique"
        ]
    }
}

I believe the issue is a result of the response not matching the error schema specified in swagger.yml: https://github.com/netlify/open-api/blob/master/swagger.yml#L2777-L2787

Start with swagger.yml around lines 2777-2787 and compare the documented error schema with the 422 response returned by the sites endpoint. Trace how that response reaches the TextConsumer and TextUnmarshaler handling. Done means the subdomain uniqueness error is represented and reported without the unsupported *models.Error message.