[SIDECAR_INVALID] sidecar-invalid-na-annotated not detected -- should this be an error?

[VisLab]

SIDECAR_INVALID sidecar-invalid-na-annotated not detected a HED. A column name should not be n/a. Not sure whether BIDS has any restrictions on columns names and whether n/a is allowed to be a column name in BIDS?

Example: Doesn't cause a validation error but specification says it should.

{
  "event_code": {
    "HED": {
      "face": "(Red, Blue),(Green, (Yellow))",
      "n/a": "(Def/MyColor, Onset), (Def/Acc/3.5 m-per-s^2)"
    }
  }
}