CloudFront Function event.request.uri contains query params

Hi

I have the following as my CloudFront Function:

function handler(event) {
    console.log(event);
    return event.request;
}

In the CloudFront console, I switch to the Test tab, and use this as URL path: /1234?param=1. When I run the test request and inspect the logs, I see the following:

{
   "version":"1.0",
   "context":{
      "distributionDomainName":"[redacted].cloudfront.net",
      "distributionId":"[redacted]",
      "eventType":"viewer-request",
      "requestId":"4TyzHTaYWb1GX1qTfsHhEqV6HUDd_BzoBZnwfnvQc_1oF26ClkoUSEQ=="
   },
   "viewer":{
      "ip":"1.2.3.4"
   },
   "request":{
      "method":"GET",
      "uri":"/index.html?q:1",
      "querystring":{
      },
      "headers":{
      },
      "cookies":{
      }
   }
}

In the Test tab GUI, if I add the params to "Query string" section, it works fine. But when I execute the request from different clients, say a browser, the query params are actually part of the event.request.uri instead of event.request.querystring.

We're expecting the params to be part of the querystring object, is this not true? Is there some sort of configurations to parse these correctly?

I have added the following screen grabs if it would help: