400 Bad Request due to attributes value

[Daniel-Ross]

I'm using this test data to migrate to 2.2.x of the SDK:

[{'key': 'test_touches_touches', 'value': 46, 'date': '2024-09-01', 'attributes': [{'owner': 'Web Order'}]}]

I get the following error when trying to push it to Databox:

An unexpected error occurred: (400)
Reason: Bad Request
HTTP response headers: HTTPHeaderDict({'Date': 'Mon, 14 Oct 2024 13:58:09 GMT', 'Content-Type': 'application/vnd.databox.v2+json', 'Content-Length': '98', 'Connection': 'keep-alive'})
HTTP response body: {"status":"BAD_REQUEST","message":"HV000028: Unexpected exception during isValid call.","id":null}

Reading through the documentation, it seems this should be correct. What am I doing wrong?