Spotify Artist can't be found

But that's exactly what I said, that this is not working!

If one artists in the whole request can't be mapped, the whole requests gets rejected :

Look at the following output, I create a list, try to add 2 artists in which requests one can be mapped and one can't and the result is, that nothing gets added to the profile. In the 2nd requests I have 2 artists that can be mapped and the results is as expected.

flybird :: ~ » curl -sS "http://developer.echonest.com/api/v4/catalog/read?api_key=$KEY&format=json&id=CAVXBQN1429442B82E&bucket=artist_location&results=0"  | beautijson
{
    "response": {
        "catalog": {
            "id": "CAVXBQN1429442B82E",
            "items": [],
            "name": "test",
            "start": 0,
            "total": 0,
            "type": "artist"
        },
        "status": {
            "code": 0,
            "message": "Success",
            "version": "4.2"
        }
    }
}
flybird :: ~ » curl -sS -X POST "http://developer.echonest.com/api/v4/catalog/update" -F "api_key=MG4EQZVZGVWV2SSEV" -F "data_type=json" -F "format=json" -F "id=CAVXBQN1429442B82E" -F 'data=[{"item":{"artist_id":"spotify-WW:artist:7dOBabd5O4CvKrg4iriHTM"}},{"item":{"artist_id":"spotify-WW:artist:53sIBaVjXQhfH89Vu6nEGh"}}]' | beautijson
{
    "response": {
        "status": {
            "code": 5,
            "message": "The Identifier specified does not exist",
            "version": "4.2"
        }
    }
}
flybird :: ~ » curl -sS "http://developer.echonest.com/api/v4/catalog/read?api_key=$KEY&format=json&id=CAVXBQN1429442B82E&bucket=artist_location&results=0"  | beautijson
{
    "response": {
        "catalog": {
            "id": "CAVXBQN1429442B82E",
            "items": [],
            "name": "test",
            "start": 0,
            "total": 0,
            "type": "artist"
        },
        "status": {
            "code": 0,
            "message": "Success",
            "version": "4.2"
        }
    }
}
flybird :: ~ » curl -sS -X POST "http://developer.echonest.com/api/v4/catalog/update" -F "api_key=MG4EQZVZGVWV2SSEV" -F "data_type=json" -F "format=json" -F "id=CAVXBQN1429442B82E" -F 'data=[{"item":{"artist_id":"spotify-WW:artist:7dOBabd5O4CvKrg4iriHTM"}},{"item":{"artist_id":"spotify-WW:artist:7bvcQXJHkFiN1ppIN3q4fi"}}]' | beautijson
{
    "response": {
        "status": {
            "code": 0,
            "message": "Success",
            "version": "4.2"
        },
        "ticket": "CAVXBQN1429442B82E082E16059E1E49"
    }
}
flybird :: ~ » curl -sS "http://developer.echonest.com/api/v4/catalog/read?api_key=$KEY&format=json&id=CAVXBQN1429442B82E&bucket=artist_location&results=0"  | beautijson
{
    "response": {
        "catalog": {
            "id": "CAVXBQN1429442B82E",
            "items": [],
            "name": "test",
            "start": 0,
            "total": 2,
            "type": "artist"
        },
        "status": {
            "code": 0,
            "message": "Success",
            "version": "4.2"
        }
    }
}

For better readability here again: http://pastebin.com/gm3z6Cw6