Given a file attachment field and given there was at least one file attached to it
When I try to submit an empty value array for this field using either the REST route PUT /artifacts/{id} or the REST route POST /artifacts
Then an error 400 Bad Request will be returned :

"Bad Request: Invalid format for file field \"452\".  Correct format is {\"field_id\" : 425, \"value\" : [457, 258]}"

Example JSON payload:

{"values": [{"field_id": 452, "value": []}]}

It was expected to be accepted as it is stated in the route documentation that this is how to empty a file field of its content.