FHIR Sandbox sort by family not available

I am playing with the FHIR Sandbox.

I want to sort the patients returned in the bundle from the Patient search using the _sort (according to FHIR standard the _sort parameter is what should be used to sort), but I get: "Invalid request URL parameter _sort specified"

So I am having to assume that InterSystems did not implement _sort.

Or it may be a named something else, why I say so is that there is something else that they "renamed", that is the "stateId" they renamed to "queryId", this refers to the stateId returned in the "Link" URL of the bundle with which you fetch subsequent pages, they nicely just went and renamed it to queryId ignoring FHIR standard? See the snippet of the link URL below.

So if they ignore FHIR standard for the stateId, then I am thinking perhaps also for _sort it was named something else. Anybody know please?

"link": [
  {
   "relation": "first",
   "url": "https://fhirsandbox.intersystems.com/csp/healthshare/hsods/fhir/stu3/Patient?_format=json&page=1&queryId=e1c61d6c-e05c-11e9-bb67-12268ceaf57a"
  },