How long does a ringout ID live for?

Firstly, ringout is working correctly, it dials two numbers and connects them together successfully.

When I send a POST request to the Ringout REST API endpoint, I get a ringout ID back. I then use this ringout ID and issue a GET request every few seconds to track when both parties have answered there calls. ( I am aware of webhooks, but webhooks don't give me the callee's status)

{  
"uri": "https://platform.devtest.ringcentral.com/restapi/v1.0/account/XXXX/extension/XXXXXX/ringout/XXx";,
  "id": xxx,
  "status": {
    "callStatus": "Success",
    "callerStatus": "Success",
    "calleeStatus": "Success"
  }
}

I use this same polling technique to work out when either party has disconnected from the call.

{  
"uri": "https://platform.devtest.ringcentral.com/restapi/v1.0/account/xxxx/extension/xxxx/ringout/xxxx";,
  "id": xxx,
  "status": {
    "callStatus": "CannotReach",
    "callerStatus": "Finished",
    "calleeStatus": "Finished"
  }
}

I noticed that the ringout ID only lives for about 30 seconds, after this time when I send a GET request I get this response even though the phone call is still taking place.

{  
"errorCode": "CMN-102",
  "message": "Resource for parameter [ringoutId] is not found",
  "errors": [
    {
      "errorCode": "CMN-102",
      "message": "Resource for parameter [ringoutId] is not found",
      "parameterName": "ringoutId"
    }
  ],
  "parameterName": "ringoutId"

}

Is this the expected behaviour for a ringout call, does the ID disappear after 30 seconds, even though the call is still active?