Validator throws ref-1 error when no reference is provided

[Kasdejong]

Validating the following patient:

{
  "resourceType": "Patient",
  "id": "Pat",
  "link": [
    {
      "id": "Link",
      "other": {
        "id": "lol",
        "display": "this is a test"
      },
      "type": "replaces"
    }
  ]
}

throws validator error:
Overall result: FAILURE (1 errors and 0 warnings) [ERROR] Instance failed constraint ref-1 "SHALL have a contained resource if a local reference is provided" (at Patient.link[0].other[0])

The invariant for this starts with "reference.exists() implies...", so this is a bug. Maybe we assign a placeholder value which we forget to check for during the validation?