API POST to /observation_photos with observation UUID returns 422

Platform (Android, iOS, Website): API (Node-based)

App version number, if a mobile app issue (shown under Settings or About):

Browser, if a website issue (Firefox, Chrome, etc) :

URLs (aka web addresses) of any relevant observations or pages:

Screenshots of what you are seeing (instructions for taking a screenshot on computers and mobile devices: https://www.take-a-screenshot.org/):

I’m not sure if this is a code bug or a documentation bug. The documentation says that the observation_photo[uuid] field is “Observation UUID”, but maybe it’s intended to be an observation photo UUID?

Description of problem (please provide a set of steps we can use to replicate the issue, and make as many as you need.):

russell@zip:~ $ curl --header "Authorization: $JWT" https://api.inaturalist.org/v1/observations/152784013  | jq '.results[0].uuid'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 74944  100 74944    0     0   130k      0 --:--:-- --:--:-- --:--:--  131k
"96689998-eec4-491a-8c62-0deaccb21871"
russell@zip:~ $ curl --header "Authorization: $JWT" --header 'Content-Type: multipart/form-data' https://api.inaturalist.org/v1/observation_photos -F "observation_photo[uuid]=96689998-eec4-491a-8c62-0deaccb21871" -F file=@_DSC1275.jpg
{"error":{"original":{"errors":"No observation specified"}},"status":422}%                                                                                              

Just to confirm, using the observation_id field does work:

russell@zip:~ $ curl --header "Authorization: $JWT" --header 'Content-Type: multipart/form-data' https://api.inaturalist.org/v1/observation_photos -F "observation_photo[observation_id]=152784013" -F file=@_DSC1275.jpg
{"id":246210022,"observation_id":152784013,"photo_id":263906257...